Strangest Things People Have Found Underwater

The ocean is big, like really big. We've only explored 5 percent of it, so there are amazing, unbelievable things we haven't even seen yet. But what we have seen is still pretty strange, and some of the stuff we've found there, even stranger:

In 2011 Swedish diving team Ocean X explored the bottom of the Baltic Sea. With a name like Ocean X, something straight out of a science fiction B-movie, they had to know they would discover something weird. And they certainly did: a weird disk laying on the bottom of the sea. It was 60 meters wide and basically looked like the Millennium Falcon had plopped down in the Baltic. Obviously, UFO hunters went nuts.

Theories lit up the internet — UFO believers thought this irrefutable proof that aliens had landed on Earth. The anomaly just looked too artificial to believe that it was naturally made. It even looked like it had stairs off to the side. More "grounded" theorists thought it was the turret of an old-school battleship or a Nazi anti-submarine mine. But that didn't fit with the dating — it was at least 20,000 years old.

Finally, scientists came along and showed that it was probably a glacial deposit. But it's a damn weird glacial deposit. UFO theorists aren't convinced, and are sure there is a government cover up. Even scientists are still arguing about exactly what caused it. So anything goes at this point. Except for the whole Falcon thing. That's just silly.

Man-made objects like roads and bridges don't belong underwater. Ancient roads belong underwater even less. But off the Bahama islands, there's an ancient road that was mysteriously laid down long ago. Or so some people think. Called Bimini Road, this is the speculated route to Atlantis.

First discovered in the '60s, Bimini Road is a bunch of stones laid down next to each other, like an underwater cobblestone road. The artifact suddenly starts and ends, implying that it's a small part of a long-lost causeway. However, the big question was: how did it get underwater in the first place? There wasn't any large civilizations centered on the Bahamas, so conspiracy theorists though that it was part of an ancient Atlantian highway.

Making things even weirder, the Bimini Road matched a prediction made in 1938 by American mythic Edgar Cayce: "A portion of the temples may yet be discovered under the slime of ages and sea water near Bimini ... Expect it in '68 or '69 – not so far away." Bimini Road got discovered in 1968.

As they usually do, scientists came up with an alternate (and probably more reasonable) explanation: this was just a really weird-looking natural rock formation. Analysis of the rocks showed no evidence of them being cut by tools. Still, it's an odd anomaly, and Edgar Cayce's shockingly correct prophesy shrouds the underwater causeway in mystical mystery.

By 1944, World War II was going really, really badly for the Japanese. Allied forces had achieved air superiority, and United States bombers could fly all over the Pacific, bombing Japanese ships without much fear of retribution. In that situation, the Japanese made the weird decision to keep the bulk of their navy in one place: the Truk Lagoon in the Caroline Islands.

The Allies launched a massive two-day air raid against the lagoon. The Japanese lost 50 ships and 250 airplanes, which was a huge chunk of their remaining fleet. There was a war to fight, so the Americans didn't have time to clean up the island — all of the sunken war material got left at the bottom of the ocean.

Divers started re-exploring the lagoon in the '60s, revealing the eerie underwater graveyard with documentary films. The ships, airplanes and tanks are in nearly pristine condition. Creepily, most of them still had the bodies of Japanese sailors inside of them. Tourists can now make a dive to the weird graveyard (the bodies have mercifully been removed), but it's not safe. Ragged metal edges of blasted ships can easily cut through skin, which would be only a minor annoyance ... if the water's weren't shark infested. But whaddya know, they are.

The old-school tech has also been leaking toxic oil and fuel into the water for 70 years now. Clearly, the ghost fleet is still trying to fight back.

Rivers are things that shouldn't exist underwater, outside of Spongebob. Turns out, though, rivers can form underwater given the right combination of water conditions. Or maybe magic. It's not too clear.

The biggest and best underwater river is in the Yucatán Peninsula. At the bottom of the sea there is a thin layer of hydrogen sulfate, which basically acts as a barrier between two layers of water. It's not something a diver will feel when passing through, but it creates a secondary body of water below the proper ocean.

This isn't just some weird formation that divers call an underwater river even though it doesn't really look like one. Fallen leaves cover the dirt banks of the river. Submerged trees dot the edges. Besides being underwater, it looks just like a normal terrestrial river.

The river is either the coolest thing we have ever seen, or one of the most unsettling. There's just nothing like it in the world, and it looks like a piece of dry land got submerged by a super angry mythical god without changing anything. How the system survives is beyond our understanding. If we had a few PhDs in oceanography, maybe we would start to understand it. But what we really can't comprehend is, how somebody hasn't made a really cool underwater horror movie about it. Get James Cameron on the phone!

Various governments around the world run ocean-listening networks. They say they're monitoring the oceans to study glaciers, volcanic activity and animal migration. But from what we can tell, governments mostly use them to record creepy sounds from the deep that sound like Cthulhu.

The most famous one was "Bloop," which everybody thought was a giant sea monster mating call, but ended up being a normal old ice shelf breaking apart. Like the most popular girl at school, Bloop attracted everybody's attention, leaving the true mysterious sounds without limelight. The coolest among them is Upsweep, a periodic rising sound that's been picked up since 1991. Unlike other weird noises, Upsweep is periodic and uniform, without the randomness we'd expect from a natural occurrence. And it just keeps showing up, with no explanation. At first, we thought Upsweep was the sound of sea water contacting underwater lava (yes that's real, so now you have another thing to waste your afternoon reading about), but the sound profile didn't match, nor did that it has been detected over and over like clockwork.

Since 1991, Upsweep has slowly gotten quieter, but it's still audible to underwater hydrophones. Even the official National Oceanic and Atmosphere Administration website says they basically have no clue why this is happening. When even the government openly admits they're stumped, we know Upsweep is caused by something amazing. Until we know for sure, sea monsters are in the realm of possibility.

The oceans are home to many an animal that hasn't really changed for millions of years — evolution just decided "yep, good enough" and stopped messing around with them. But these creatures have nothing on a group of microbes found at the bottom of the ocean who win the survivor award, hands down — they have stayed alive since the Jurassic period.

A group of European researchers discovered them while digging sediment cores in the ocean. When they analyzed the dirt, they found a colony of microbes that seemed barely alive. Test showed that the oldest microbes in the colony were 86 million years old — they had somehow survived all these years without food or sunlight. That's one hell of a diet.

The microbes have such an unbelievably slow metabolism, it takes them 1,000 years to divide. In contrast, E. Coli cells divide every 17 minutes. So without cool scientific tools, you'd have to watch these ancient creatures for 1,000 years to even prove they were alive. It's amazing to think about how much history had passed by the oldest cells in the colony. Thankfully, a stray submarine torpedo didn't blow them up.

The coolest thing about them is that it shows how resilient single-celled organisms are, adding to the likelihood of finding single-celled life in space. We're sure that space microbes, and our Jurassic microbes, would have amazing stories to tell, if only they had prehistoric mouths with which to gab.

When rockets shot into space in the '60s and '70s, scientists weren't too concerned where the boosters engines and other equipment landed when jettisoned. As long as it didn't smash into a residential area, they were fine with it falling somewhere in the ocean. Basically, NASA was a bunch of heartless space litterers.

Rockets parts are scattered among Earth's oceans, but it's nearly impossible to find them. That didn't deter Amazon founder Jeff Bezos. In 2012, he assembled a secret dive team to try to find the F-1 engines that shot the Apollo missions into orbit. But he wasn't just content with any old engines — he wanted the ones from Apollo 11, the mission that landed men on the Moon. After tons of searching, they found them, laying 14,000 feet below the ocean surface.

The engines were in remarkably good shape, for hunk of metals that dropped from space and slammed into the ocean. Bezos recovered them and quickly contacted NASA. Like clingy children, NASA claimed legal ownership over the engines they hadn't seen in over 40 years. Bezos turned them over without a fuss, proving he's better than us. We would have tried to hide them as long as possible ... at least, until our landlords get mad at us, despite the rules not saying a thing about not being able to stash a rocket in our apartment.

UFO researchers love speculating about crop circles, even though they're almost certainly just pranks pulled by bored rural kids. While the "normal" crop circles aren't super mysterious anymore, when they started popping up at the bottom of the ocean, they raised more than a few skeptical eyebrows.

Divers off the coast of Japan started seeing the weird patterns in 1995, each one about seven feet in diameter. This seemed like another sign aliens were hanging out on Earth, only now they were drawing weird pictures in the sand. That's a weird pastime for aliens but, fortunately for their reputation, it turns out the underwater crop circles are naturally occurring.

Honestly, the real explanation isn't that much weirder than aliens — male pufferfish are the culprits. They spend ten days creating the circular pattern, to impress lady pufferfish. During mating season, the ladies swim around the ocean looking for the coolest circles, and lays her eggs in the middle of the ones she finds the best. Nobody knows how the female pufferfish make their decision but, evidently, they have extremely refined aesthetic taste.

The male pufferfish gets the worst part of the deal. The female pufferfish doesn't stay around, and he has to raise the eggs. Once they hatch, he doesn't even get to spend time hanging out with the baby fish. Nope, it's simply on to the next patch of sand to build another nest. For his whole life, he's just making circles in the sand. That sounds depressing, but he is just a fish, and they aren't well-known for having existential crises.

Throughout the ocean, there are groups of little manganese nodules hanging out, slowly growing. How they grow isn't too much of a mystery: manganese gets dissolved in the ocean water, and slowly accretes on other clumps of the metal. And we mean slowly. The little metal balls grow only one centimeter every million years, so they've been around a really long time. Because they're so easy to harvest, mining companies were pumped when they were discovered, and now some of them harvest the metal from the ocean surface.

Finding vast beds of metal balls on the ocean floor is weird enough — it's even stranger that scientists don't know how they even started in the first place. A 42-day expedition was launched to figure it out, but they found out nothing. Theorists believe they might have been started by ancient underwater microbes, or they're just a natural result of ancient oceans, which might have been more metallic. But let's be honest, it's gotta be aliens. Let's just go with that.

The Fury and Helca Straight is a body of water in the Qikiqtaaluk region of Nunavut, Canada, which sounds like the coolest name in the world for a geographic region. The awesome name of the region isn't what makes it famous, though — it's the mysterious sounds coming from the water.

All throughout the summer, boatmen on the water hear mysterious humming or pinging sounds. Oddly, the sounds travel only through the water, and are audible when they reverberate through the hulls of boats. It's a super-weird occurrence, almost like the ocean is trying to use Canadian boats to send a message to the human race.

Nobody knows why it's happening, though there are a ton of theories going around, most of them blaming Baffinland Iron Mines Corporation mining, Arctic research stations or Greenpeace conservation efforts. How conservation efforts create mysterious pinging sounds is beyond us, but all the groups investigated, and couldn't find anything they were doing to create it. So now the locals are really creeped out.

Even the military stepped in to try to figure out what is going on — nothing was discovered. So as of now, the sounds still remain an utter mystery. Qikiqtaaluk might not have been on anybody's list as a paranormal hotspot, but things are definitely spooky up in the frozen North. We just hope it isn't the White Walkers.

War is expensive business, and the last thing that England wanted in World War II was to lose to the Nazis, just because they were strapped for cash. Before the Internet and world-wide banking, that meant silver and gold from the Empire had to be put on a ship and sailed around the world. That's super dangerous when Nazi U-boats are in the waters.

In 1942, the SS City of Cairo sailed from India, with 100 tons of silver to help out the war effort. Shockingly, they decided to sail without escort. To the surprise of absolutely no one, a U-boat found the ship and blew it to pieces. Oddly, the captain of the submarine felt super-bad about it, surfaced his boat, yelled to the survivors in life boats, "sorry for sinking you" and disappeared back under the water. Meanwhile, all those silver coins sunk to the bottom of the ocean.

For decades, $50 million of silver just sat at the bottom of the ocean, with only the fish around to use it. Finally, it was rediscovered (because fish are stingy and don't like to spend money), and the United Kingdom financed a team to grab it, probably with strict orders to take none of the coins for themselves. Upon retrieval, all the money was returned to England, melted down, and sold off. Too bad — if it was us, we probably would have made a Scrooge McDuck-style, coin-filled swimming pool.

When working on an oil rig, the last thing anybody wants is a giant sea monster to show up. But that's exactly what happened in 2012 when cameras on an oil rig in the Gulf of Mexico picked up ... something. Out of nowhere, a huge amorphous blob of flesh appeared, circling the rig, freaking people out, and disappearing back into the ocean.

What was the thing? The video shows a bunch of details that don't look like an Earth creature. The sea monster looked like a big brown sheet of flesh but had reproductive organs and something that looked like a network of nerves. Clearly, this was alien life.

The actual explanation isn't much less weird than extraterrestrial visitors. Biologists identified the creature as Deepstaria engimatica, which sounds like the coolest progressive metal band ever. This massive jellyfish looks more like a misshapen blob of brown flesh than the pretty, delicate jellyfish that we see in aquariums. It's rarely seen and usually hangs out in deep water, where it grows to absurd sizes. Part of the issue with studying the species is that it's too big for most submersibles to take it as a sample.

Okay, so biologists now know what it was, but why did the jellyfish try to come hang out with an oil rig? They aren't known for friendliness, and they aren't exactly the smartest of creatures. But for some reason, this giant specimen took a liking to our oil rig. Hopefully they aren't planning some sort of takeover.

All over the oceans, researchers set up underwater listening devices, usually to track whales. Every whale species has distinctive calls, so whale fans can easily identify what they're listening to. At least, until they heard the 52-Hertz whale. Since 1989, this whale has stumped researchers because it's the only one in existence that calls at that specific frequency.

What is going on with this lonely whale? People tracking the whale (named 52) say that it always travels alone. They have never heard it with other whales or heard any other whales calling at 52-Hertz. Most likely, 52 is looking for other whales of its species, constantly calling out for some company. No other whales of his species ever hear him. 52 is totally alone.

Nobody knows exactly how this happened. Most likely, he belongs to a totally different species of whale that we haven't identified. If that's the case, where are the other members of his species? He might very well be the last one, which provides tons of tantalizing mysteries about what happened to his species. Even weirder, nobody has ever seen the lonely cetacean. He has only ever been heard, like a ghost in the ocean. One day we might find him, but for now 52 is an inspirational icon for people who love solitude.

This is a case of where the mystery comes from when explorers didn't find something underwater. In this case, a whole island. Bermeja was an island off the coast of Mexico that appeared on maps as far back as the 17th century. But sometime around the 1800s, the whole island disappeared.

People keep looking for it in its last known location. The British supposedly found the island in 1844, reporting it a few hundred feet below the ocean surface. Nobody could verify their claims, and the island became an urban legend. At least, it was an urban legend before it blew up into a full-blown conspiracy.

Believers uncovered a 1857 map from the United States that featured Bermeja. Mexican maps and documents included the island up to 1946. Obviously, the government believed it existed. According to discovered documents, the Mexican government sent out an expedition to the location in 1997 but reported there was nothing there. The last known mention of the island is in a 1998 Mexican book.

So what's going on here? If the island existed, it was above the water at least until 1844. In 1997, the Mexican and United States governments agreed to drill for oil off the coast of Mexico, and then poof, the island supposedly stops existing. A lot of people think the island was deliberately blown up for some nefarious purpose. These aren't just crackpot conspirators: Mexican senators are on record pushing this conspiracy theory. That still wouldn't explain the British claim though. Something weird is happening, and Bermeja better be the topic of Indiana Jones 5.

The United States National Oceanic and Atmospheric Administration operates a ton of hydrophones that listen for strange noises in the water. They were first put in place to pick up Soviet submarines but now they pick up weird noises that sound like alien life or deep-sea monster calls.

The most popular one is the Bloop, which sounded like Cthulhu's mating call. Even though Bloop sounded organic, it's most likely the sound of an iceberg breaking in two, which is nearly as cool. Bloop is the most popular of the NOAA mystery noises, but the other ones are even more interesting.

There's Julia, which creepily sounds like somebody moaning into the hydrophones. The sound is oddly organic, but the NOAA claims it's totally just ice and nothing that anybody needs to worry about. They would. Another weird one is Train, a constant hum that echoes through the Antarctic and sounds like a, you guessed it, train going over tracks. It's consistent, but the NOAA still hasn't quite figured it out.

Our favorite mysterious sound is Whistle. Whistle is really weird because it happened only once and was picked up by only one hydrophone. That's super unusual because usually these sounds echo through the ocean and get picked up by multiple hydrophones. We think it might be a sea monster, but the NOAA says that it was probably an underwater volcano blowing up, which we didn't even know is a thing. Honestly, we don't know which explanation is cooler.

In 2015, the Gulf of Alaska experienced a "whale-pocalypse" when thirty carcases were found in the gulf. Nobody knows what happened. One whale death is a tragedy, but thirty bumping off at once is a mystery.

Marine biologists can tell the whales weren't intentionally beaching themselves and were dying in the water first, which means something horrible has happened in the waters off the Gulf of Alaska. Leading theories say a bloom of poisonous algae probably did them in, which is terrifying in its own right. Algae can just randomly pop up and murder a big pod of whales? Remind us never to go swimming again.

But the idea of seas that suddenly turn poisonous is the most reasonable solution to the problem. We are sure we can dig up some crazy conspiracies involving deep-sea killer squids, interspecies civil war, or Kirk and Spock doing a really bad job retrieving whales to defeat the Whale Probe. Oddly, this isn't the first time it happened either. The NOAA has recorded 62 similar events since 1991, and only a third of them have been solved. What is killing off our whales, and why can't anybody figure it out?

Over the past few decades, whales have been acting weird. For some reason, modern whales are singing lower and lower each year.

It's a really weird mystery. This isn't just one group of whales singing deeper—whales around the world are doing the same thing, at the same rate. Whales from different parts of the world are dropping the pitch of their calls at the same time but without being physically around each other. The songs seem like the whales are coordinating them, but that's impossible. It's happening quite quickly too. They're now singing 30 percent lower than how they were singing in the 1960s.

Countless explanations come up in marine biology communities. Unfortunately, none of them involve whale ESP or whales trying to do their best Leonard Cohen impersonation. The leading theory is that since whales are dying off, they have to drop the tone of their calls to make it resonate better in the water, since it has to travel farther to reach another whale. Others marine biologists think the whales are responding to new ocean dynamics or noise pollution. Our favorite theory is that they have developed a new mating strategy, almost like they had a whale sexual revolution, those frisky whales.

Stonehenge is creepy enough as is, but finding another Stonehenge underwater? That's just too much for us to handle. That's exactly what divers found though, in what we used to think wasn't a very mysterious place: Lake Michigan.

The lake isn't well known for archaeological mysteries, so when divers found the ring of stones under the water, it was a huge surprise. The structure looks just like the Stonehenge on the British Isles and got constructed in 10,000 BC. The stones have the familiar circular pattern and even have a carving of a mastodon in them. Because they're underwater, they have degraded much more than the above-water Stonehenge. Researchers can still see the pattern though. Nobody really knows how they got there, or why they bear such a resemblance to Stonehenge.

Our biggest problem is that doing research requires scientists to go underwater, which isn't ideal conditions to do scientific work. Leading theories say that back in ancient history, Lake Michigan was dry, and climate change slowly filled it up with water. Okay, we can buy that, but it doesn't really explain how the ancient Michiganders decided to build the same stone ring as the people on the other side of the Atlantic. Did they have contact with the ancient people of the British Isles, or did ancient Michiganders and ancient Brits descend from the same group of people? Whatever the case, this made Michigan 500-percent more mysterious than it was before. We don't want to say aliens did it, but ...