The depths of the world’s oceans and seas are the hiding place of many extraordinary enigmas and phenomena. From an ancient city famous for its fish sauce, to fish that make art and from secret WWII code machines to 2,000 year-old computers, you never know what will turn up next. We’ve rounded up 20 of the most awesome things found by divers as they explore the depths – read on to be amazed.
20. Great Blue Hole, Belize
The extraordinary Great Blue Hole, set in the Caribbean Sea off the coast of Belize, is the largest sinkhole anywhere in the world. Many divers had explored the upper waters of the hole, which is 410 feet deep and 984 feet wide. But they hadn’t gone down to the depths for a very good reason. At around 290 feet the sinkhole is blanketed by a layer of highly poisonous hydrogen sulfide.
But in 2018 an expedition that included British tycoon Richard Branson and Fabien Cousteau, son of the legendary Jacques, found a way to explore the depths of the Great Blue Hole. The explorers used a three-person mini-submarine to reach the parts that no human diver could survive in. At the bottom they found stalactites, indicating that this was once a dry cave, probably flooded around 14,000 years ago when the last Ice Age ended. The submarine crew also made another much grimmer discovery – the bodies of two divers.
19. Chuuk Lagoon
Chuuk Lagoon, formerly known as Truk, is some 40 miles across at its widest and, according to The New York Times, is the “biggest graveyard of ships in the world.” The lagoon is located in a far-flung section of the central Pacific and belongs to the Federated States of Micronesia. The reason so many shipwrecks are sunk in the lagoon is the massive two-day naval battle that took place there in 1944. The U.S. Navy sank more than 30 Japanese vessels during the clash.
Back in the 1960s, recreational divers started to explore the lagoon, and it was popularized by a 1969 Jacques Cousteau documentary, Lagoon of Lost Ships. The pristine waters of the lagoon offer superb visibility, and all those sunken Japanese ships and planes provide “one of the great underwater wonders of the world,” diver Paul J. Tzimoulis, wrote in Skin Diver Magazine. If you ever dive there, just watch out for the live ammo!
18. Yonaguni Pyramid
The uppermost part of the massive stone structure that lies close to the shores of the Japanese island of Yonaguni is just a few feet below the water’s surface. According to the Japanese geologist Masaaki Kimura, this mysterious formation is actually a man-made pyramid, sunk beneath the ocean. He points to the stepped flanks, signs of a mason’s hand and features resembling gates, stairs and canals as evidence for his claim that the pyramid is part of a 5,000-year-old city.
But despite the undoubted magnificence of the rock formations, there are many who are decidedly skeptical of Kimura’s extravagant claims. One such is Professor Robert Schoch of Boston University. In 2007 he told National Geographic magazine, “I’m not convinced that any of the major features or structures are manmade steps or terraces, but that they’re all natural.” So pyramid or natural formation? Why not take a trip to Yonaguni, drag on your wetsuit, and decide for yourself.
17. The Franklin Expedition’s lost ships
H.M.S. Terror and H.M.S. Erebus embarked on a groundbreaking Arctic exploration in 1845 under the leadership of Sir John Franklin. The British expedition encountered impassable ice and abandoned its flagship, Erebus in the floes; Terror also foundered later. All of the 129 men that made that fateful journey to the Arctic lost their lives. The location of the lost vessels remained a mystery for nearly 170 years.
Then an expedition mounted by Parks Canada found Erebus in 2014, lying in shallow waters south of King William Island. Two years later, searchers found the wreck of the Terror about 45 miles from Erebus and 160 feet underwater. Divers sent a remotely controlled underwater drone into the interior of Terror, capturing astonishing images of the well-preserved cabins. Flatware, bottles, and even the captain’s desk were all clearly visible, a haunting remembrance of the pioneers who died exploring the frozen Arctic.
16. Cenote Angelita
A cenote, the Merriam-Webster online dictionary tells us, is, “a deep sinkhole in limestone with a pool at the bottom.” They’re not rare and are most commonly found in Mexico where there are thousands. But Cenote Angelita near Tulum on the Yucatan Peninsula is no run-of-the-mill sinkhole. If you dive into Angelita’s waters, you’ll see an amazing site. An underwater river no less.
That’s right, in the depths of the Cenote Angelita, an apparent river runs under the sea. If you dive down into the cenote, you’ll come to an easily visible layer of water that’s quite different than the liquid above and below it, a kind of cloudy section. This is actually dissolved hydrogen sulfide, which has accumulated over the years, a product of organic material that’s fallen to the bottom of the pool and decomposed. For all the world, this layer has the appearance of a ghostly river.
15. The Antikythera mechanism
Antikythera is a small Greek island in the Mediterranean Sea. Sometime in the first century B.C., during the height of the Roman Empire, a ship came to grief of the shores of the island. Some 2,000 years later, at the dawn of the 20th century, divers searching for sponges happened upon the wreck. It proved to be rich source of ancient wonders including splendid statues wrought from bronze and marble.
But the star find was something that came to be known as the Antikythera mechanism. It’s a sophisticated instrument that sailors would have used to aid navigation by making astronomical observations. The machine consists of three bronze disc with toothed gears and rings with markings that denote degrees. And the incredible thing is that nothing this old and this complex has ever been found before or since. Discoveries of comparable complexity are some 1,000 years younger. Indeed, one researcher called it “an ancient Greek computer.”
In the Red Sea, about 1,300 feet off the coast of Israel, lies a lost village some 30 feet under the water. But it’s not a settlement that was overwhelmed by recent global warming. Atlit-Yam, as it’s called, is actually a human habitation that dates right back to the Stone Age. And its position under the surface of the Red Sea means it is one of the best-preserved settlements from that era anywhere in the world.
Systematically explored by divers in the 1980s, Atlit-Yam was flooded by the sea at the end of the past Ice Age. However, by then it seems that the village had already been engulfed by a tsunami, although there was life there until around 7,000 B.C. The site includes the ruins of stone dwellings, paved yards, and the remains of more than 60 of its inhabitants. But the most impressive feature is a half-circle of seven standing stones, each weighing more than a thumping eight tons.
13. S.S. Thistlegorm
It was Jacques Cousteau and his diving team aboard the Calypso that first did a detailed exploration of the S.S. Thistlegorm back in 1955. The shipwreck lies in the Egyptian section of the Red Sea, off the shores of the Sinai Peninsula at a depth of around 100 feet. Bombs from a German plane sunk the 415-foot cargo vessel in 1941. Nine sailors lost their lives in the attack.
Today, divers flock to the Thistlegorm’s wreck to see its fascinating cargo as it rusts away in the sea. Included in the ship’s holds are almost intact trucks, motorcycles and military supplies of every kind. There are Lee Enfield rifles, standard issue British WWII weapons. Bren gun carriers, tracked light vehicles armed with machine guns, are among the cargo, and there are even two steam locomotives. It’s a veritable underwater museum.
The ancient city of Thonis-Heracleion, near the spot where the River Nile runs into the Mediterranean off northern Egypt, has a lot of history. As mythology has it, this is the location where the Greek god Heracles, perhaps better known as Hercules, first arrived on the continent of Africa. But the great city was lost in an earthquake some 2,000 years ago, engulfed by the sea.
A British Royal Air Force officer first spotted ruins beneath the sea as he flew over them in 1933. But it wasn’t until the early 2000s that divers made a breakthrough discovery. They found a fragment of the monumental sculpture of Hapy, who had guarded the entrance to the Nile for hundreds of years until the second century B.C. Subsequent dives unearthed more evidence of the lost city including temples, jewelry, ceramic shards, and oil lamps.
11. Temple of Doom
Cenote Esqueleto is a sinkhole near Tulum in Mexico that has been dubbed the Temple of Doom. It gets its name because it’s a difficult and potentially dangerous dive. The only way to enter the cenote is to jump in: there’s no ladder to allow easy access. So you’re putting yourself in a potentially perilous situation from the get-go.
Once you’re in the cenote, you’ll find that there are areas of deep darkness. Divers are advised to stick to the waters where sunlight falls. Esqueleto leads to a network of underground caves. These too can be extremely hazardous with the danger of losing your way in the darkness. So, all in all, this is a dive best left to people with plenty of experience under their (weight) belts.
In 1967 Dr. Nicholas Flemming, a marine geo-archaeologist at the University of Southampton in England, was diving off the coast of Greece. He noticed some anomalous rock formations in the sea. The next year, a team from Cambridge University conducted a detailed survey of the site. It turned out to be an extensive city that had been lost to the waves.
Divers have found as many as 15 buildings as well as roads and tombs under the sea in what is now called Pavlopetri, the name of a nearby island. The structures lie at a depth of between around six and ten feet, and it’s likely that the city was immersed after an earthquake some 2,000 years ago. So Flemming’s casual dive all those years ago unearthed one of the most significant finds of a lost city ever made.
9. The Mary Rose
If you think of diving as a thoroughly modern pursuit, think again. The wreck of the Mary Rose was discovered by intrepid underwater explorers, brothers John and Charles Deane, in 1836. In fact the Deane brothers were the inventors of the diving helmet. They discovered the Mary Rose in the Solent, the strait that runs between the southern coast of England and the Isle of Wight in the English Channel.
The Mary Rose was a 600-ton warship launched in 1511 when Henry VIII, a keen commissioner of naval ships, was on the throne of England. She met her end in 1545 at the hands of England’s bitter enemy, the French. The Deanes discovered the wreck after a tip-off from local fisherman who complained that something was continually snagging their nets. The location of the ship was then lost until a diver rediscovered her in 1971. In 1982 about half of the Mary Rose was raised from the seabed, and it’s now on display at Portsmouth Historic Dockyard in England.
8. The coelacanth
Unless you’re an expert in marine life, you might well be scratching your head and asking, “What’s a coelacanth?” The answer is: a prehistoric fish. In fact, until relatively recently it was known only through fossil finds, and experts believed it was long extinct. Scientists thought it had breathed its last around 65 million years ago around the same time that the dinosaurs disappeared. But this wily fish had everyone fooled, experts included.
It was first discovered by a museum curator, Marjorie Courtenay-Latimer, who found it aboard a trawler that had docked at the South African port of East London. The fish had been scooped from the ocean in the boat’s nets. The first scuba divers to see coelacanths actually alive in the sea found a population of them in 2000 at Sodwana Bay, off the South African coast. Coming face to face with a creature supposedly extinct for 65 million years must surely have sent a shiver down the spine.
7. U.S.S. Nevada
Commissioned in 1916, the U.S.S. Nevada was the only ship to get into action during the Pearl Harbor attack in 1941. Badly damaged during the Japanese assault and afterwards beached, she was refurbished and returned to service. Nevada went on to see action both during the invasion of Europe in 1945 and in the battles fought in the Pacific during WWII. But after her wartime combat heroics, fate dealt the ship a strange card.
U.S.S. Nevada was chosen as a target for the first atom bomb test at Bikini Atoll. Remarkably, she survived even that ordeal and was only finally sunk in 1948 by U.S. Navy practice gunfire. Her final resting place was only discovered in May 2020 by a team of divers using a remotely controlled vehicle. Now we know that the (almost) unsinkable ship lies almost three miles beneath the ocean surface about 80 miles southwest of Pearl Harbor.
6. Stone Age settlement
In 2016 divers were exploring just off the coast of southern Sweden when they came across an extraordinary find: a Stone Age village from some 9,000 years ago. Among the artifacts that the team discovered was an axe-head fashioned from elk antler, which is marked with intriguing inscriptions. Also unearthed were eight fish traps made from woven hazel branches.
The flooded settlement is located under 65 feet of the Baltic Sea about two miles from the Swedish coast. One of the researchers from Sweden’s Lund University explained in a short film from the university that the settlement was now underwater because sea levels had risen after the last Ice Age ended. He added, “Humans have always preferred coastal sites as we do today.” So it seems, just like us, our ancient ancestors loved to be beside the seaside.
5. Mysterious sand circles
It was in 1995 when some divers noticed something very odd on the sandy seafloor off the coast of Japan. What they saw were circular patterns marked in the sand, which incorporated intricate geometric patterns. In fact, these were strongly reminiscent of crop circles and looked very much like something made with human skill.
But these patterns had not been created by any human hand. Yet how exactly these patterns were appearing beneath the waves was a complete mystery. It took ten years of surveillance before the true authors of these beautiful motifs, up to seven feet across, emerged. It turned out that the artists were actually a type of puffer fish. And it’s all about sex. The male puffer fish, about five inches from mouth to tail, creates these amazing underwater artworks to attract a mate.
4. Battle site from 2,200 years ago
The naval Battle of the Aegates, also called the Battle of the Egadi Islands, was a fiercely fought engagement that took place in 241 B.C. The combatants were the Carthaginians of north Africa and the Romans, two peoples struggling for supremacy in the Mediterranean. Classical scholars will tell you that it was the final decisive battle of the First Punic War, and the Romans emerged the victors.
Starting in 2005, a team of divers searched for years for the site of this historic clash near the Egadi Islands, which lie to the west of Sicily. Success was limited until the real breakthrough came in 2017 after years of largely unsuccessful searching. In that year and the next, 19 rams were uncovered, the weapons attached to the prows of ancient battleships and used to batter opponents. This discovery confirmed that the divers really had found this historic naval battle site.
Neapolis was a thriving city on the Mediterranean coast of modern Tunisia with its own economic niche a couple of thousand years ago. The good folk of the city, it seems were experts at making something called garum. This was a fermented fish condiment much favored by the ancient Greeks and Romans. Made from fish guts and salt, it doesn’t sound that appetizing, but folks back in the Classical era apparently couldn’t get enough of it.
But Neapolis’s fish sauce industry and its very existence came to a dramatic and catastrophic end 365 A.D. when it was engulfed by a tsunami. The 50-acre site of the city lay undiscovered on the seabed until 2017 when divers from Italy and Tunisia found it after seven years of searching. The underwater ruins of Neapolis include buildings, streets, and monuments, plus around 100 tanks that would have been used to make that pungent fish sauce.
Some German divers were on a mission to recover ditched fishing nets from the Baltic Sea in December 2020 when they made a strange find. At first, they thought they’d discovered a rusty old typewriter, although what that was doing on the Baltic seabed was a puzzle. But one of the divers, archaeologist Florian Huber, was soon able to identify the rusting lump of metal. It was a German Enigma coding machine, used during WWII to scramble messages.
A German submarine had likely discarded the Enigma machine. At the end of the war, the Nazis ordered U-boat crews to scuttle their vessels and to dispose of the Enigma machines they carried to avoid them falling into Allied hands. But this was a pointless act since, unbeknown to the Germans, the British had famously deciphered the Enigma codes at Bletchley Park where the legendary Alan Turing had worked his magic.
1. H.M.S. Victory
H.M.S. Victory was a British Royal Navy man-of-war shipwrecked in 1744 with the loss of 1,100 mariners. It’s worth pointing out that this Victory sailed the seas before Admiral Horatio Nelson’s Victory, his flagship and the site of his death at the Battle of Trafalgar in 1805. Nevertheless, the earlier Victory was a significant ship of its day. The 100-gun sailing vessel sank in the English Channel, probably in a severe storm.
The precise location of the Victory’s wreck remained a mystery for some 250 years. But in 2009 the wreck site was finally pinpointed by a Florida-based diving outfit, Odyssey Marine Exploration. The remains of the great ship lie in some 250 feet of water, so salvaging of artifacts was difficult to say the least. But two of her bronze cannons, a 12-pounder and a massive 42-pounder have been successfully brought to the surface, finally confirming the ship’s identity.