1 00:00:00,000 --> 00:00:08,400 Do the sounds of the ocean hold the key to the biggest aviation mystery of modern times? 2 00:00:08,400 --> 00:00:11,400 If the aeroplanes there, they'll find it. 3 00:00:11,400 --> 00:00:16,600 What's behind the discovery of a bizarre body on the high seas? 4 00:00:16,600 --> 00:00:21,000 How can a man be mummified on a boat drifting in the middle of the ocean? 5 00:00:22,000 --> 00:00:28,400 And is a ghostly entity appearing to adventurers in extreme peril? 6 00:00:28,800 --> 00:00:31,400 Is it magic? Is it faith? What is it? 7 00:00:34,400 --> 00:00:39,400 The underwater realm is another dimension. 8 00:00:39,400 --> 00:00:48,400 It's a physically hostile place where dreams of promise can sink into darkness. 9 00:00:48,400 --> 00:00:50,400 I'm Jeremy Wade. 10 00:00:50,400 --> 00:00:57,400 I'm searching the world to bring you the most iconic and baffling underwater mysteries known to science. 11 00:00:57,400 --> 00:01:00,400 Shipwrecks can't just disappear, or can they? 12 00:01:00,400 --> 00:01:04,400 It's a dangerous unexplored frontier that swallows evidence. 13 00:01:04,400 --> 00:01:08,400 We know more about the face of Mars than we do our deepest oceans. 14 00:01:08,400 --> 00:01:13,400 Where unknown is normal and understanding is rare. 15 00:01:13,400 --> 00:01:33,400 On March 8th, 2014, Malaysia Airlines Flight 370 departs Kuala Lumpur with 239 passengers 16 00:01:33,400 --> 00:01:37,400 and crew bound for Beijing, China. 17 00:01:37,400 --> 00:01:39,400 It never arrives. 18 00:01:39,400 --> 00:01:45,400 Years later, the fate of MH370 remains a mystery. 19 00:01:45,400 --> 00:01:51,400 But now, pioneering science involving a new way of listening to the ocean 20 00:01:51,400 --> 00:01:54,400 offers to unlock the location of the missing aircraft 21 00:01:54,400 --> 00:01:59,400 and solve the greatest aviation mystery of modern times. 22 00:01:59,400 --> 00:02:09,400 Malaysia Flight 370 contacts the Chinese Air Force 0-9. 23 00:02:09,400 --> 00:02:12,400 Malaysia Flight 370. 24 00:02:14,400 --> 00:02:18,400 They communicated to Indonesian air traffic control. 25 00:02:18,400 --> 00:02:23,400 It was supposed to be handed off to Vietnamese aircraft control, and it just disappeared. 26 00:02:23,400 --> 00:02:28,400 A real vexing part of this mystery is that the pilot says good night, 27 00:02:28,400 --> 00:02:32,400 but then the plane turns off course. 28 00:02:32,400 --> 00:02:38,400 The transponder then gets switched off, and then the aircraft, MH370, 29 00:02:38,400 --> 00:02:42,400 flies along scenes of radar lines outside of radar coverage. 30 00:02:42,400 --> 00:02:44,400 There's no distress call. 31 00:02:44,400 --> 00:02:47,400 There are no calls from cell phones, from the passengers. 32 00:02:47,400 --> 00:02:50,400 Just complete silence. 33 00:02:50,400 --> 00:02:55,400 What happened to the flight has haunted the world ever since. 34 00:02:55,400 --> 00:02:58,400 We're not used to planes just disappearing. 35 00:02:58,400 --> 00:03:03,400 If they come down, we expect to be able to find out why. 36 00:03:03,400 --> 00:03:08,400 An international team of reconnaissance aircraft with naval support 37 00:03:08,400 --> 00:03:12,400 combs the vast Indian Ocean for signs of the plane. 38 00:03:16,400 --> 00:03:19,400 Analysis of satellite data and drift modelling 39 00:03:19,400 --> 00:03:25,400 identifies an area of the Indian Ocean that searches dub the Seventh Ark. 40 00:03:25,400 --> 00:03:31,400 The Seventh Ark is determined by the experts to be the maximum distance a plane could have reached 41 00:03:31,400 --> 00:03:34,400 dependent on the fuel that was in the plane. 42 00:03:34,400 --> 00:03:41,400 Experts narrow down the hunt to a section of the Ark, 2,000 miles off the coast of Western Australia. 43 00:03:44,400 --> 00:03:47,400 But the search team faces huge challenges. 44 00:03:47,400 --> 00:03:52,400 The average depth of the Indian Ocean is over 12,000 feet. 45 00:03:52,400 --> 00:03:55,400 The deep ocean is truly the abyss. 46 00:03:55,400 --> 00:04:01,400 We often think of the land as being mountainous, but that compared to the ocean is a smooth pebble. 47 00:04:04,400 --> 00:04:08,400 And although satellites and radar can aid in the search from above, 48 00:04:08,400 --> 00:04:11,400 they can't penetrate the deep ocean. 49 00:04:11,400 --> 00:04:15,400 Anything deeper than 200 metres is very poorly explored. 50 00:04:15,400 --> 00:04:18,400 It's hard to get to and there's no light down there. 51 00:04:18,400 --> 00:04:22,400 We don't have accurate maps of the seabed in that area. 52 00:04:22,400 --> 00:04:27,400 Unable to see in the dark waters, the search team adopts a different method. 53 00:04:27,400 --> 00:04:35,400 Once you start to look below the surface, really sound is the best tool that we have. 54 00:04:35,400 --> 00:04:42,400 So we have to convert that sound search into a visual picture 55 00:04:42,400 --> 00:04:45,400 and that's effectively what Sonar is doing. 56 00:04:45,400 --> 00:04:52,400 We call it mowing the lawn and you just have to work those transits back and forth, back and forth, back and forth until you find something. 57 00:04:52,400 --> 00:05:00,400 Autonomous and remotely operated vehicles sweep the ocean floor with Sonar looking for the stricken plane. 58 00:05:00,400 --> 00:05:06,400 They allow you to get deep enough for long enough to map the seafloor at incredible depths. 59 00:05:06,400 --> 00:05:13,400 The team combs an area of 46,000 square miles, but nothing is found. 60 00:05:19,400 --> 00:05:24,400 For over a thousand days, the Australians have been looking in different locations. 61 00:05:24,400 --> 00:05:30,400 And I mean, it's an airplane. I never thought that it wasn't found yet. 62 00:05:30,400 --> 00:05:38,400 Dr Usama Kadri, a mathematician and expert in fluid dynamics, is frustrated by the lack of progress. 63 00:05:38,400 --> 00:05:40,400 But he has an idea. 64 00:05:40,400 --> 00:05:50,400 If MS-870 would have impacted on the surface, I started thinking, would actually that create acoustic gravity waves. 65 00:05:50,400 --> 00:05:56,400 When an object hits the sea's surface, it causes a sudden change in water pressure, 66 00:05:57,400 --> 00:06:03,400 which creates a special type of sound wave called an acoustic gravity wave. 67 00:06:03,400 --> 00:06:07,400 They don't only reside at the surface, they reside everywhere. 68 00:06:07,400 --> 00:06:11,400 We're talking about 4,000 metres, the average depth of the ocean. 69 00:06:11,400 --> 00:06:17,400 In addition, acoustic gravity waves can travel many hundreds of miles. 70 00:06:17,400 --> 00:06:24,400 By tracking these waves, it should be possible to work out the time an object struck the water. 71 00:06:24,400 --> 00:06:28,400 And potentially its location in the ocean. 72 00:06:28,400 --> 00:06:38,400 So, could an acoustic gravity wave caused by the impact of MH-370 unlock the secret of its final resting place? 73 00:06:38,400 --> 00:06:47,400 If MS-870 impacted on the surface of the ocean, that impact should have been recorded. 74 00:06:47,400 --> 00:06:52,400 Do we have some underwater recordings for these waves? 75 00:06:53,400 --> 00:06:59,400 Across the planet's ocean floor lie listening posts called hydrophones. 76 00:06:59,400 --> 00:07:06,400 These underwater microphones convert sounds in the ocean into electrical signals that can be measured. 77 00:07:06,400 --> 00:07:13,400 They're used from everything from tracking whales to tracking submarines. 78 00:07:13,400 --> 00:07:20,400 So did hydrophones record an acoustic gravity wave made by MH-370 when it hit the water? 79 00:07:20,400 --> 00:07:27,400 Hydrophones are incredibly sensitive, so something impacts the surface a thousand miles away, it will still be heard. 80 00:07:27,400 --> 00:07:31,400 And there's an international organisation that's listening. 81 00:07:31,400 --> 00:07:40,400 The CTBTO, the Nuclear Test Ban Treaty Organisation, operates hydrophone stations around the world. 82 00:07:40,400 --> 00:07:47,400 Listening out 24-7 for evidence of unsanctioned nuclear weapons testing. 83 00:07:51,400 --> 00:07:58,400 Dr Kadri's hope is that they may have inadvertently captured the impact of MH-370. 84 00:07:58,400 --> 00:08:06,400 I asked to have all available data in the Indian Ocean that they have from hydrophones that might be related to MH-370. 85 00:08:06,400 --> 00:08:14,400 From before the airplane took off until the very possible time that you can have on that flight. 86 00:08:14,400 --> 00:08:23,400 One listening station sits at Cape Luhin on the southwest tip of Australia, close to the original search site. 87 00:08:23,400 --> 00:08:28,400 We focused on the ones from Cape Luhin which is nearer to the 7th arc. 88 00:08:28,400 --> 00:08:35,400 There were two signals that could have been related to MH-370. 89 00:08:35,400 --> 00:08:40,400 Frustratingly, the signals he finds are very weak. 90 00:08:40,400 --> 00:08:49,400 But there's another CTBTO station in the Indian Ocean whose signals have not yet been investigated. 91 00:08:49,400 --> 00:08:59,400 This is over 3,000 miles away to the northwest on the tiny and remote militarised island of Diego Garcia. 92 00:08:59,400 --> 00:09:04,400 If you blindly trusted 7th arc, then you wouldn't even look there at this data. 93 00:09:04,400 --> 00:09:12,400 Is this really going to be a way that we can turn back the clock to the origin of the MH-370's loss at sea? 94 00:09:12,400 --> 00:09:23,400 It is a long shot, but Dr Kadri believes that hydrophone recordings from Diego Garcia could help pinpoint the impact of MH-370 in the ocean 95 00:09:23,400 --> 00:09:30,400 and thereby be the key that opens up the investigation into the missing aircraft. 96 00:09:30,400 --> 00:09:36,400 But when he gets his hands on the recordings, vital data is missing. 97 00:09:36,400 --> 00:10:05,400 The disappearance of flight MH-370 has baffled the world for years, but now a radical new technique that hunts sound waves underwater 98 00:10:05,400 --> 00:10:11,400 could pinpoint the aircraft's impact site in the ocean. 99 00:10:11,400 --> 00:10:20,400 The initial search for MH-370 in the South Indian Ocean has been the largest and most expensive in history. 100 00:10:20,400 --> 00:10:32,400 Millions and millions of dollars have been spent, thousands and thousands and thousands of hours of vessels doing survey in the Indian Ocean. 101 00:10:32,400 --> 00:10:38,400 But what if they've been looking in the wrong place? 102 00:10:38,400 --> 00:10:49,400 Now, a new theory is pointing to a different area, 3,000 miles away, where underwater recordings could hold the key to the mystery. 103 00:10:49,400 --> 00:10:59,400 They couldn't find the airplane in the very same place that they thought that it should be, so I really wanted to analyse all the signals. 104 00:10:59,400 --> 00:11:09,400 But when Dr. Cardre finally gets his hands on the relevant recording data from the Diego Garcia listening station, crucial information is missing. 105 00:11:09,400 --> 00:11:19,400 When we got the data, for each hour you get one file. You notice that was one file that has half of the size. 106 00:11:19,400 --> 00:11:28,400 There's a 25-minute hole in the recordings and it's vital data from right around the time that the plane disappeared. 107 00:11:28,400 --> 00:11:35,400 All these three hydrophones, it seems that they were shut down at the same time. 108 00:11:35,400 --> 00:11:42,400 The reason that we believe it's shut down because of the way the signal looks like when it restarts. 109 00:11:42,400 --> 00:11:48,400 We wanted to know why there is a missing 25 minutes. 110 00:11:48,400 --> 00:11:55,400 Was the hydrophone turned off due to some type of technical issue that was anticipated? 111 00:11:56,400 --> 00:12:03,400 The missing data has opened up a further mystery and yet more speculation. 112 00:12:03,400 --> 00:12:07,400 Would there be the threat of a rogue nation intercepting data? 113 00:12:07,400 --> 00:12:15,400 Could it have been interference from other states who for their own reason are finding ways to switch off the hydrophones? 114 00:12:15,400 --> 00:12:21,400 Requests from Dr. Cardre's team for answers are met with silence. 115 00:12:21,400 --> 00:12:32,400 The missing 25 minutes is absolutely vital because if we had those 25 minutes then we would actually know almost certainly whether we're talking about MH370. 116 00:12:32,400 --> 00:12:44,400 Undeterred by this unforeseen setback, Dr. Cardre digs into the remaining data from Diego Garcia and finds something astonishing buried deep inside the recordings. 117 00:12:44,400 --> 00:12:50,400 From Diego Garcia, there are a couple of signals that were found. 118 00:12:50,400 --> 00:12:55,400 One of these mysterious signals could be the impact of MH370. 119 00:12:55,400 --> 00:13:08,400 If it is, it means the plane took a route no one has yet examined and it could launch a brand new investigation into what really happened in the final hours of the ill-fated flight. 120 00:13:08,400 --> 00:13:13,400 Usama Cardre and his colleagues are giving us a new perspective on this mystery. 121 00:13:13,400 --> 00:13:17,400 If the aeroplane is there, they'll find it. 122 00:13:17,400 --> 00:13:23,400 Much detailed data analysis remains to be done by Dr. Cardre and his team. 123 00:13:23,400 --> 00:13:39,400 But in time his investigations could trigger a new search in a brand new area, bringing fresh hope to the families of the missing and perhaps finally solving this terrible tragedy, one of the most enduring mysteries of the deep. 124 00:13:39,400 --> 00:13:52,400 What is the disturbing secret beneath the decks of a stricken boat drifting in the middle of the ocean? 125 00:13:52,400 --> 00:13:56,400 He was literally mummified, basically turned to leather. 126 00:13:56,400 --> 00:14:02,400 What happened here? What happened to the captain? What happened to the vessel? 127 00:14:10,400 --> 00:14:27,400 My investigations on and under the water have brought me face to face with the bizarre, the unexplained and the downright horrific. 128 00:14:27,400 --> 00:14:37,400 But just when you think you've seen it all, the waters throw up an even more disturbing phenomenon, a mummified man in the middle of the ocean. 129 00:14:44,400 --> 00:14:47,400 January 31st, 2016. 130 00:14:47,400 --> 00:14:56,400 The clipper around the world yacht race is in full flow through the western Pacific on its fifth leg from Australia to Vietnam. 131 00:14:56,400 --> 00:15:00,400 Leading the pack is the Elmax Exchange. 132 00:15:00,400 --> 00:15:08,400 500 nautical miles west of Guam, they come across a disconcerting site. 133 00:15:08,400 --> 00:15:11,400 They find a stricken vessel with a broken mast. 134 00:15:11,400 --> 00:15:16,400 There's a code of the sea that says you don't leave your fellow mariner in peril. 135 00:15:16,400 --> 00:15:21,400 They went over to see if the vessel was in distress, nobody came out. 136 00:15:21,400 --> 00:15:27,400 The ocean is always moving and so it's impossible for them to really pull up alongside each other. 137 00:15:27,400 --> 00:15:35,400 So it was necessary for the crew of the race boat to pull up nearby and send someone to swim across. 138 00:15:35,400 --> 00:15:42,400 The crew member manages to battle his way to the stricken yacht and clamber aboard. 139 00:15:42,400 --> 00:15:44,400 What he found was horrific. 140 00:15:45,400 --> 00:15:51,400 A dead sailor slumped over his charts, seemingly frozen in time. 141 00:15:51,400 --> 00:15:57,400 I can't imagine climbing aboard a vessel to offer assistance and finding a dead person on board. 142 00:15:57,400 --> 00:16:00,400 It must have been horrifying. 143 00:16:00,400 --> 00:16:04,400 How long has he been sitting there dead? 144 00:16:04,400 --> 00:16:08,400 How did he die? Was it foul play? Was he injured? 145 00:16:08,400 --> 00:16:14,400 One thing that's really eerie is that you look at the way that he's frozen the position, he's slumped over the table. 146 00:16:14,400 --> 00:16:20,400 He may have known he was having some kind of medical issue going for the radio to say SOS help. 147 00:16:20,400 --> 00:16:29,400 There's no sign of a struggle or injury and certain obvious clues that would be available on land are missing. 148 00:16:30,400 --> 00:16:41,400 Often the first things to arrive at a dead body will be flies and their maggots can actually give us a timeline for how long that body's been dead. 149 00:16:41,400 --> 00:16:46,400 But in this case we don't have that. Out in the middle of the ocean there aren't any flies. 150 00:16:46,400 --> 00:16:51,400 The race crew called the Coast Guard. The Coast Guard said they'll take care of the issue. 151 00:16:51,400 --> 00:16:54,400 Basically race on, we've got this. 152 00:16:54,400 --> 00:17:01,400 The racing yacht continues on her way but no one comes to deal with the stricken vessel. 153 00:17:01,400 --> 00:17:07,400 Fast forward 26 days, 600 miles away near the Philippines. 154 00:17:07,400 --> 00:17:12,400 A group of fishermen come across the very same boat. 155 00:17:12,400 --> 00:17:17,400 The gentleman who was in it, who expired, was still at his same position. 156 00:17:17,400 --> 00:17:26,400 It's unbelievable that he was drifting for so long and so far how he wasn't picked up by the authorities, no one knows. 157 00:17:26,400 --> 00:17:30,400 And something bizarre has happened to him since he was last seen. 158 00:17:30,400 --> 00:17:38,400 This is where the mystery really begins because they find him at the table, slumped over, but he looks like a mummy. 159 00:17:41,400 --> 00:17:45,400 He was literally mummified, basically turned to leather. 160 00:17:45,400 --> 00:17:51,400 What happened here? What happened to the captain? What happened to the vessel? 161 00:17:51,400 --> 00:17:57,400 The mummified sailor is brought ashore and the local police start searching for clues. 162 00:17:57,400 --> 00:18:01,400 A few new pieces of information come to light. 163 00:18:01,400 --> 00:18:05,400 This yachtsman was very, very experienced. He'd gone all over the world. 164 00:18:05,400 --> 00:18:12,400 He'd been sailing from 2008 almost continuously, first with his wife and then on his own. 165 00:18:12,400 --> 00:18:17,400 The autopsy concludes that the most likely cause of death was a heart attack. 166 00:18:17,400 --> 00:18:25,400 But it can't explain how the body has completely dried out, just three feet from a vast expanse of water. 167 00:18:25,400 --> 00:18:33,400 The fact that he was found in this sort of mummified state is a pretty curious thing. 168 00:18:33,400 --> 00:18:37,400 When we think of mummification, we of course think of Egypt. 169 00:18:38,400 --> 00:18:45,400 Ceremonial mummification was practiced in Egypt and parts of America and Asia for thousands of years. 170 00:18:45,400 --> 00:18:55,400 To prepare a dead body for the afterlife, internal organs and all liquid were removed to prevent rotting and aid preservation. 171 00:18:55,400 --> 00:18:59,400 So by removing a lot of these internal organs, you're also removing the moisture. 172 00:18:59,400 --> 00:19:06,400 That was one of the ways that they tried to slow down the decomposition process and promote the mummification. 173 00:19:07,400 --> 00:19:15,400 This process took months and involved surgery, elaborate ritual and a wide range of minerals and ointments. 174 00:19:15,400 --> 00:19:19,400 And it was carried out in the driest places on the planet. 175 00:19:19,400 --> 00:19:26,400 So what miracle created this modern day mummy in the middle of the ocean in just 26 days? 176 00:19:26,400 --> 00:19:31,400 This hasn't been observed before, so it's something quite new and quite mysterious. 177 00:19:32,400 --> 00:19:37,400 How did it happen? And how did it happen so fast? 178 00:19:52,400 --> 00:19:56,400 A lone sailor has naturally mummified in the middle of the ocean. 179 00:19:56,400 --> 00:20:03,400 All we know is that he died of a heart attack and this shocking transformation happened within a month. 180 00:20:03,400 --> 00:20:11,400 How on earth can a process which normally takes twice that time with assistance happen in the middle of the ocean on its own? 181 00:20:14,400 --> 00:20:19,400 What kind of conditions must have been present on this vessel in order for him to become mummified? 182 00:20:20,400 --> 00:20:27,400 On land, natural mummification can occur in extremely cold or arid environments, 183 00:20:27,400 --> 00:20:34,400 or when a body is deprived of oxygen. Famous examples have been found around the globe. 184 00:20:34,400 --> 00:20:38,400 There's an ice man basically preserved within the ice. 185 00:20:39,400 --> 00:20:49,400 For over 5,000 years, Otsi the Iceman lay in snow and ice in the Tyrol mountains of Italy, where his body slowly dehydrated. 186 00:20:49,400 --> 00:20:52,400 Or there's people who sink down into bogs. 187 00:20:53,400 --> 00:20:58,400 The Tolland man was found buried in Peat near Silkeborg in Denmark. 188 00:20:58,400 --> 00:21:05,400 His head startlingly well preserved after more than 2,000 years in an oxygen-deprived bog. 189 00:21:06,400 --> 00:21:13,400 But few examples exist of mummification happening naturally when surrounded by the ocean. 190 00:21:13,400 --> 00:21:16,400 There's sort of a preservation process happening. 191 00:21:16,400 --> 00:21:24,400 So you need to have a situation where insects and things that you normally have on land that would promote decomposition aren't actually there. 192 00:21:25,400 --> 00:21:29,400 But there are other, much more powerful factors at play. 193 00:21:30,400 --> 00:21:36,400 The mummification process here was likely a combination of the heat and the wind. 194 00:21:37,400 --> 00:21:42,400 We know that the yacht would have been quite warm, and we also know that there was a hatch left open, 195 00:21:42,400 --> 00:21:45,400 and there would have been a bit of a breeze coming through the ship. 196 00:21:45,400 --> 00:21:52,400 If you have a contained space that's being heated up by the sun, that can become incredibly hot and powerful, 197 00:21:52,400 --> 00:21:59,400 with air continually flowing through, warming up and dehydrating this body over time. 198 00:21:59,400 --> 00:22:05,400 In addition to heat and wind, experts speculate that another element might be a factor, 199 00:22:05,400 --> 00:22:09,400 and it's something found in abundance in the sea. 200 00:22:09,400 --> 00:22:14,400 The Egyptians would use natron, which was a form of salt that would be used to preserve the body. 201 00:22:14,400 --> 00:22:16,400 He was in a salty environment. 202 00:22:16,400 --> 00:22:23,400 If you're bathing, usually you're bathing with salt, so it's entirely possible that he had salt on his skin. 203 00:22:23,400 --> 00:22:27,400 And perhaps the sea salts behaved like the natron in this case. 204 00:22:28,400 --> 00:22:37,400 But for their mummification process, the ancient Egyptians would cover the corpse with large quantities of natron. 205 00:22:37,400 --> 00:22:43,400 So could a much smaller quantity of sea salt have had the same effect? 206 00:22:43,400 --> 00:22:47,400 And one other vital question still remains. 207 00:22:47,400 --> 00:22:51,400 How could this transformation happen in just 26 days? 208 00:22:51,400 --> 00:22:56,400 Less than half the time it took the ancient Egyptians. 209 00:22:56,400 --> 00:23:01,400 In just the right conditions, mummification can happen quite quickly. 210 00:23:01,400 --> 00:23:05,400 Something that they refer to as precocious mummification. 211 00:23:05,400 --> 00:23:13,400 Precocious mummification has been observed to occur in confined spaces and specific microclimates. 212 00:23:13,400 --> 00:23:17,400 Maybe it was a perfect storm of conditions. 213 00:23:17,400 --> 00:23:29,400 But exactly how a process that naturally can take a year and with assistance several months can happen in weeks and at sea is still unclear. 214 00:23:29,400 --> 00:23:34,400 It's a mystery as to why that happened over the period of time that it did. 215 00:23:36,400 --> 00:23:47,400 The ocean usually swallows its victims without a trace, but this one is preserved for the annals of science by a process that may never be fully understood. 216 00:23:48,400 --> 00:24:05,400 Many of our greatest cities were born out of the ocean, ports providing safe haven from storms, enemies and deep sea creatures. 217 00:24:05,400 --> 00:24:10,400 San Francisco has always been faced by an additional threat. 218 00:24:10,400 --> 00:24:12,400 Earthquakes. 219 00:24:12,400 --> 00:24:23,400 Now an amazing discovery of ships underground may mean that the city's nautical past could threaten its future when the next big one strikes. 220 00:24:31,400 --> 00:24:34,400 Down below there's something hidden. 221 00:24:34,400 --> 00:24:37,400 I think the people wouldn't believe it. 222 00:24:37,400 --> 00:24:45,400 In 1978, workmen digging foundations in downtown San Francisco make a remarkable discovery. 223 00:24:45,400 --> 00:24:49,400 And it's the first of many. 224 00:24:49,400 --> 00:24:58,400 When construction workers are digging tunnels for the metro or foundations for large buildings, they're constantly finding the remains of ships. 225 00:24:58,400 --> 00:25:04,400 Over 60 shipwrecks are known to be in the harbor area or the downtown business corps. 226 00:25:04,400 --> 00:25:07,400 But where have these ships come from? 227 00:25:07,400 --> 00:25:13,400 You're finding razor blades, you're finding bottles, you're finding all kinds of goods that these people were taking with them. 228 00:25:13,400 --> 00:25:17,400 Is this an ancient shipyard? Is this a burial ground? 229 00:25:17,400 --> 00:25:22,400 It's like, holy cow, how'd this ship get three blocks from the sea? 230 00:25:22,400 --> 00:25:28,400 San Francisco is not the only coastal city where this phenomenon has come to light. 231 00:25:29,400 --> 00:25:34,400 It's happening in cities like New York, for example, when they rebuilt the Twin Tower. 232 00:25:34,400 --> 00:25:37,400 They actually found a shipwreck at the bottom of the new site. 233 00:25:37,400 --> 00:25:41,400 The same thing has been found in Istanbul and in places all around the world. 234 00:25:41,400 --> 00:25:45,400 What is unique about San Francisco is you have so many. 235 00:25:45,400 --> 00:25:51,400 It's really one of the largest collections of shipwrecks that have survived in a land context. 236 00:25:51,400 --> 00:25:57,400 The more ships archaeologists find, the more they notice a strange connection. 237 00:25:57,400 --> 00:26:03,400 They are all from the same era, 170 years ago. 238 00:26:03,400 --> 00:26:10,400 So what happened in the mid-19th century that created this extraordinary ship cemetery? 239 00:26:10,400 --> 00:26:15,400 The answer is gold. 240 00:26:16,400 --> 00:26:19,400 January 24, 1848. 241 00:26:19,400 --> 00:26:23,400 Flakes of gold are discovered at Caloma, California. 242 00:26:23,400 --> 00:26:30,400 San Francisco is the nearest port for thousands of wannabe prospectors. 243 00:26:30,400 --> 00:26:36,400 The population of San Francisco exploded from 1,000 people to 25,000 people. 244 00:26:36,400 --> 00:26:43,400 People were coming from all over the world, so you had this river of men flowing in from the ocean. 245 00:26:43,400 --> 00:26:46,400 It was like a huge parking problem. 246 00:26:46,400 --> 00:26:52,400 The desire for gold is so strong that the new arrivals, including many crews, 247 00:26:52,400 --> 00:26:58,400 desert their ships and head straight for the gold fields. 248 00:26:58,400 --> 00:27:04,400 I think at one point there are over 900 vessels just abandoned in San Francisco Harbor. 249 00:27:04,400 --> 00:27:10,400 It must have looked like hundreds of trees without any limbs. 250 00:27:10,400 --> 00:27:14,400 But how do they end up creating new land? 251 00:27:14,400 --> 00:27:19,400 Scuttling ships is the purposeful sinking of vessels. 252 00:27:19,400 --> 00:27:23,400 Often they're filled with rocks or they're filled with sediment, 253 00:27:23,400 --> 00:27:28,400 or they have big piles driven through them in order to keep them in place. 254 00:27:28,400 --> 00:27:33,400 They started to fill the in-between spaces in with refuse and dirt and all kinds of things 255 00:27:33,400 --> 00:27:39,400 to basically fill in the area around and in between the ships to make land. 256 00:27:39,400 --> 00:27:44,400 Starting from shore they would just accrete out another vessel, another vessel, another vessel. 257 00:27:44,400 --> 00:27:53,400 And thanks to a loophole in San Francisco Law, if you sank a ship you could claim it as land. 258 00:27:53,400 --> 00:27:59,400 And boom, you own a piece of waterfront property in San Francisco. 259 00:27:59,400 --> 00:28:05,400 170 years later, these boats are now the skeletons of the city's past 260 00:28:05,400 --> 00:28:09,400 and the foundations of a 21st century gold rush. 261 00:28:09,400 --> 00:28:15,400 It is one of the tech centers of the United States. It's an incredibly important region. 262 00:28:15,400 --> 00:28:20,400 But is there a downside to this urban expansion? 263 00:28:20,400 --> 00:28:27,400 When you build a city like San Francisco on fill that's comprised of old shipwrecks, 264 00:28:27,400 --> 00:28:31,400 it's not the most stable platform. 265 00:28:31,400 --> 00:28:35,400 And what also adds to the challenge is when you're living near an active fault line 266 00:28:35,400 --> 00:28:38,400 like the San Andreas fault line. 267 00:28:38,400 --> 00:28:43,400 You start thinking about, hang on this, it's going to hold up in the next seismic event. 268 00:28:43,400 --> 00:28:46,400 Yeah, I wouldn't want to be there for the next big one. 269 00:28:58,400 --> 00:29:03,400 Shipwrecks underwater are amazing to dive. 270 00:29:03,400 --> 00:29:08,400 They're eerie places that echo their tragic pasts. 271 00:29:08,400 --> 00:29:18,400 But in San Francisco, buried shipwrecks underground may point to a tragic future. 272 00:29:18,400 --> 00:29:24,400 It's not the most stable platform, especially for big modern buildings. 273 00:29:24,400 --> 00:29:29,400 This is just sediment. This is just timbers which have rotted away. 274 00:29:29,400 --> 00:29:34,400 This is just ships which have slowly collapsed down into the ground or been swallowed by mud. 275 00:29:34,400 --> 00:29:39,400 You can live on it with no problem until there's a problem. 276 00:29:46,400 --> 00:29:51,400 San Francisco is located in one of the most seismically active places in the world. 277 00:29:51,400 --> 00:29:59,400 The San Andreas fault lies three miles from San Francisco, running through deep water just outside the bay. 278 00:29:59,400 --> 00:30:04,400 The San Andreas fault is the boundary between the Pacific plate and the North American plate. 279 00:30:04,400 --> 00:30:10,400 It runs parallels in San Francisco, which makes the city susceptible to devastating earthquakes. 280 00:30:10,400 --> 00:30:17,400 The fault has shown its deadly force many times, most destructively in 1906, 281 00:30:17,400 --> 00:30:21,400 when over four square miles of the city were levelled, 282 00:30:21,400 --> 00:30:27,400 and the inferno that followed destroyed some 28,000 buildings. 283 00:30:27,400 --> 00:30:31,400 3,000 people are believed to have died. 284 00:30:31,400 --> 00:30:42,400 A century later, there remains a 72% probability of the city being hit by a high-magnitude earthquake in the next 30 years. 285 00:30:43,400 --> 00:30:49,400 And such a large section of the downtown area is built on sand and ships. 286 00:30:49,400 --> 00:30:56,400 As well as the obvious damage above ground, earthquakes can have a dramatic impact beneath our buildings. 287 00:30:56,400 --> 00:31:06,400 Liquifaction is the process whereby vibrations from an earthquake liquefy the sediments deposited in an area, 288 00:31:06,400 --> 00:31:10,400 making it act as though it is water. 289 00:31:11,400 --> 00:31:15,400 Heavier structures that are sitting on top of that land that's unconsolidated 290 00:31:15,400 --> 00:31:19,400 can actually sink into the sediments. 291 00:31:19,400 --> 00:31:24,400 A city consumed by liquefaction is not without precedent. 292 00:31:24,400 --> 00:31:26,400 There's the case of Port Royal Jamaica. 293 00:31:26,400 --> 00:31:33,400 In a single morning, it went from a vibrant city into submerged into the ocean several meters. 294 00:31:33,400 --> 00:31:35,400 That was liquefaction. 295 00:31:36,400 --> 00:31:40,400 The area of San Francisco where the ships have been unearthed 296 00:31:40,400 --> 00:31:45,400 is one of the most prone to liquefaction in the whole of California. 297 00:31:45,400 --> 00:31:50,400 But do the buried ships make this natural instability worse? 298 00:31:50,400 --> 00:31:54,400 So the ship structures might actually be better than just fill, 299 00:31:54,400 --> 00:31:58,400 because you still have all the fill, but then also the ship structures. 300 00:31:58,400 --> 00:32:02,400 I don't know that being built on top of old ships is going to make a difference, 301 00:32:02,400 --> 00:32:06,400 given the fact that those high rises are buried into bedrock. 302 00:32:06,400 --> 00:32:12,400 Bedrock is hard rock beneath surface soil and substraatta that can help support large structures. 303 00:32:12,400 --> 00:32:17,400 But in the heart of the city, cracks have already appeared. 304 00:32:17,400 --> 00:32:22,400 The Millennium Tower, which was only built in 2009, has already sunk 16 inches 305 00:32:22,400 --> 00:32:26,400 and is leaning about 2 inches. 306 00:32:26,400 --> 00:32:29,400 The foundations of the city's third tallest skyscraper 307 00:32:29,400 --> 00:32:33,400 were installed in dense sand 80 feet down. 308 00:32:33,400 --> 00:32:37,400 This is something as of serious concern for the residents there. 309 00:32:37,400 --> 00:32:41,400 The skyscraper has been certified as safe. 310 00:32:41,400 --> 00:32:47,400 But the next big one, a major earthquake with the destructive power to bring down buildings, 311 00:32:47,400 --> 00:32:51,400 has long been feared by the citizens of San Francisco. 312 00:32:51,400 --> 00:32:55,400 The question is, when will it come? 313 00:32:55,400 --> 00:32:59,400 It's a huge mystery when these earthquakes will occur. 314 00:32:59,400 --> 00:33:04,400 And even if we could predict them, we'd be powerless to prevent them. 315 00:33:07,400 --> 00:33:11,400 So a city born of the sea is still in its grip. 316 00:33:11,400 --> 00:33:16,400 But how much San Francisco's high-tech future will be brought down to earth 317 00:33:16,400 --> 00:33:19,400 by the skeletons of its maritime past? 318 00:33:19,400 --> 00:33:22,400 We'll have to wait and see. 319 00:33:26,400 --> 00:33:27,040 The World's Greatest 320 00:33:33,400 --> 00:33:39,400 Being out in the vastness of the ocean alone can be a disturbing and sometimes terrifying experience. 321 00:33:39,400 --> 00:33:44,400 But what would it be like to be a solo sailor after weeks out on the water 322 00:33:44,400 --> 00:33:49,400 and to suddenly be overcome by the sensation that you're not, in fact, alone? 323 00:33:49,400 --> 00:33:54,400 This is exactly what happened to a man in the 1970s as he battled a massive storm. 324 00:33:56,400 --> 00:33:58,400 The World's Greatest 325 00:34:00,400 --> 00:34:04,400 1973, Cape Horn, Chile. 326 00:34:04,400 --> 00:34:13,400 Caught in treacherous conditions in notorious seas, his world-famous 63-year-old yachtsman, Bill King. 327 00:34:13,400 --> 00:34:17,400 He's attempting to circumnavigate the globe solo, 328 00:34:17,400 --> 00:34:23,400 but a once-in-a-lifetime storm is threatening to take him and his boat down. 329 00:34:23,400 --> 00:34:29,400 Encountering storms at sea is terrifying and it's physically exhausting. 330 00:34:32,400 --> 00:34:37,400 You're up for hours on end at the wheel in heavy concentration. 331 00:34:37,400 --> 00:34:43,400 What do you do? You're in a stressful situation. It's just like, how do you get through it? 332 00:34:45,400 --> 00:34:48,400 After two days, he's on the brink of collapse. 333 00:34:48,400 --> 00:34:53,400 When something remarkable happens, something otherworldly. 334 00:34:53,400 --> 00:34:59,400 It's pretty dire and then he feels the presence of somebody there with him, 335 00:34:59,400 --> 00:35:07,400 which gives him the reassurance to go below and be able to check his position and chart his course. 336 00:35:08,400 --> 00:35:12,400 But this incredible tale is not an isolated incident. 337 00:35:12,400 --> 00:35:20,400 Explorers across the world and throughout time claim a guardian angel has appeared and guided them to safety. 338 00:35:21,400 --> 00:35:26,400 To modern researchers, this phenomenon is known as the third man. 339 00:35:27,400 --> 00:35:32,400 Shackleton experienced it on his escape from Antarctica. 340 00:35:32,400 --> 00:35:41,400 He reported there was another individual that gave him the courage to survive and to escape with his comrades. 341 00:35:41,400 --> 00:35:51,400 Ernest Shackleton's extraordinary journey to save his entire stranded crew is considered one of the most heroic survival stories of the modern era. 342 00:35:52,400 --> 00:35:59,400 So who or what is the strange apparition that appeared to him and to sailor Bill King? 343 00:36:00,400 --> 00:36:08,400 Is it an imaginary friend that we create to help comfort ourselves? Is it a hallucination from not sleeping? 344 00:36:09,400 --> 00:36:13,400 What are they? Who knows? Is it magic? Is it faith? What is it? 345 00:36:25,400 --> 00:36:33,400 In 1973, sailor Bill King is losing a life or death solo struggle against an epic storm 346 00:36:33,400 --> 00:36:38,400 when he experiences a mysterious being that science cannot explain. 347 00:36:39,400 --> 00:36:44,400 This feeling of presence is known today as the third man. 348 00:36:47,400 --> 00:36:56,400 Even though he's alone in the middle of the ocean and he knows he's alone, mentally he's got this idea that when he's not on deck, somebody else is watching the ship. 349 00:36:57,400 --> 00:37:03,400 For a few days, he's sharing the responsibilities with this person that he feels is there. 350 00:37:04,400 --> 00:37:11,400 Up to a point where he even goes to sleep and he actually tries to stay quiet when he thinks the other person is resting. 351 00:37:14,400 --> 00:37:20,400 Once he got through this stressful situation, the sensation left and he was on his own again. 352 00:37:21,400 --> 00:37:29,400 Is this presence a physical manifestation? Who or what is it? Is it mind generated? Is it physical? 353 00:37:30,400 --> 00:37:34,400 What we do know is that it isn't just experienced on the surface. 354 00:37:35,400 --> 00:37:45,400 The ocean is a dynamic environment and it pushes people to the limit. Whether you're racing around the world on a sailboat solo or whether you're diving. 355 00:37:46,400 --> 00:37:56,400 In 1997, Stephanie Schwabbe, a world renowned diver, found herself minutes from running out of air when diving off the Bahamas. 356 00:37:57,400 --> 00:38:05,400 She describes feeling the presence of her dead husband coming to her aid and helping her to the surface just in time. 357 00:38:06,400 --> 00:38:10,400 Imagine what a relief that might be if you're off in the ocean by yourself. 358 00:38:10,400 --> 00:38:20,400 These people had the presence, the third man presence, until they knew they were going to be safe and it was like after they're safe, boom, gone. 359 00:38:21,400 --> 00:38:32,400 As well as appearing to adventurers in extreme situations, the third man has been experienced by people going through different types of ordeal including brain injury and bereavement. 360 00:38:33,400 --> 00:38:46,400 If you are overtired, hungry, cold, haven't slept for hours and you have built up stresses and the human body reacts in different ways and not only in the body, the human mind. 361 00:38:47,400 --> 00:38:57,400 In Lausanne, Switzerland, a team of neuroscientists are pioneering attempts to understand the third man with a unique experiment. 362 00:38:58,400 --> 00:39:03,400 A blindfolded participant rigged to a robot makes movements with his finger. 363 00:39:04,400 --> 00:39:10,400 These patterns are then replicated by a robotic arm on the person's back with a small time delay. 364 00:39:10,400 --> 00:39:20,400 The scientists are observing their subjects have a disconnect between where that sensation is actually coming from. 365 00:39:21,400 --> 00:39:34,400 The researchers believe that the illusion of feeling another person nearby is caused by us misperceiving the source and identity of some brain signals and this can result in an unsettling experience. 366 00:39:34,400 --> 00:39:38,400 Some of them asked to stop being part of the study because it freaked them out so much. 367 00:39:39,400 --> 00:39:44,400 They didn't want to continue because it's like what's this outside my body experience. 368 00:39:45,400 --> 00:39:52,400 Even though test subjects know a robot is pressing on their back, the feeling of presence is still experienced. 369 00:39:53,400 --> 00:39:59,400 Just like Bill King knew he was alone but still felt another being on the boat. 370 00:40:00,400 --> 00:40:07,400 But why does this phenomenon feel benevolent to those in the wild yet disturbing in the laboratory? 371 00:40:08,400 --> 00:40:11,400 Can scientists really recreate the situation in a lab environment? 372 00:40:12,400 --> 00:40:15,400 Can they recreate the ghostly presence? Can they recreate the stress? 373 00:40:16,400 --> 00:40:24,400 Because ultimately the person in the lab knows they're in the lab not in a boat alone in the middle of the ocean facing Mother Nature's fury. 374 00:40:25,400 --> 00:40:36,400 Perhaps in a life or death situation stress shatters our normal understanding of reality causing a kind of guardian angel to appear when we need it most. 375 00:40:40,400 --> 00:40:46,400 There are still many unanswered questions. Why can't we summon the third man at will? 376 00:40:47,400 --> 00:40:53,400 And why doesn't every person in extreme danger experience the helping hand of this benign entity? 377 00:40:54,400 --> 00:40:57,400 People just freak out and die and never have this third man experience. 378 00:41:00,400 --> 00:41:08,400 Some people have equated this to ghosts and apparitions and mariners are superstitious by nature. 379 00:41:09,400 --> 00:41:15,400 Is it evidence of something bigger? Perhaps. What that is is a mystery. 380 00:41:16,400 --> 00:41:24,400 Part of me hopes that I will never experience the third man but another part is not so sure. 381 00:41:25,400 --> 00:41:35,400 Those who have lived through it give us hope that deep within us there is a power to survive the most extreme situations we could ever imagine.