Exploring the vast sea has always been an exciting experience for both divers and sea explorers. Not only does it allow you to snorkel past colorful reefs, but you're also able to meet a whole bunch of exotic species while in the sea. Indeed, the whole journey does sound like another cool episode from Drain The Ocean on National Geographic. Admittedly, you never truly know what deep-sea monsters could be patrolling the “final frontier” before you enter the darkest, deepest parts of the sea. And even though you may be a well-skilled and trained diver, the following discoveries will undoubtedly question everything you might have heard or read about the sea.

Realistically, only a tiny percentage of the oceans has ever been explored by scientists, and that leaves us with wandering minds and imaginary concepts about what really goes on underwater. Also, most of these random findings are so strange and unexpected that they will surely leave you in a state of confusion.

From ancient computers, sunken airplanes, and lost underwater kingdoms, today we’ll be taking a close-up look at 22 of the most mysterious and unexplained objects found in the sea.

22 The Baltic Sea Anomaly

Back in 2012, a Swedish team of treasure seekers made the discovery of their careers that was eventually identified as "The Baltic Sea Anomaly." Actually, this happens to be quite a mysterious structure sitting more than 200 feet beneath the surface.

According to fistylelife.com, the image was considered a considerably low-tech sonar device that is famous for yielding photos that can look a bit physically distorted.

But from another perspective, this sonar device might have been a mere rock outcropping or even an odd structure distorted from the glacial movement. But like always, the world just ran pretty wild with speculation and all sorts of suggestions about the nature of this thing.

21 The Antikythera Mechanism

Have you heard about the Antikythera mechanism before?

This odd artifact was an actual analog computer used to predict the changes of astrological bodies as well as the movements of eclipses.

The first of its kind was produced somewhere between 205 and 100 BCE. Fistylelife.com reveals that the ancient analog machine was sitting on the seafloor when a group of Greek divers unwittingly came across the bizarre-looking object. Eventually, the Antikythera mechanism was fully recovered in the early 1900s and is presently on display at the National Archaeological Museum of Athens, where it regularly piques the curiosity of divers, historians, and random visitors.

20 The Apollo 11 Rocket Engines

Another curious item that was found on the sea floor turned out to be part of the famous Apollo 11 space rocket.

The CEO of Amazon.com, Jeff Bezos, launched an expedition to recover parts of the rocket engines, which somehow detached from the Saturn V about 40 miles above Planet Earth, then crashed into the deep sea.

Typically, such an unfortunate ending would suggest that the rocket was lost forever; however, Jeff’s expedition did manage to locate the parts, fistylelife.com says. In fact, the team of Jeff Bezos - this business magnate - managed to discover both engines of The Apollo rocket engines.

19 The Sunken Pyramid

A gigantic sunken pyramid was found between the islands of Terceira and Sao Miguel in Portugal, and according to thetalko.com, the pyramid dates as far back as the last ice age (which happens to be about 20,000 years ago). The estimated height of the odd pyramid, which somehow ended up on the seabed, is about 60 meters but the tip of the massive structure goes beyond 40 feet below the surface. Although the structure truly resembles a perfectly-formed human-made pyramid from the old days, experts are still uncertain about its unusual nature and true origins. After all, you don't get to see underwater pyramids every single day, do you?

18 The Yonaguni Monument

The mysterious waters of the Japanese Island, known as Yonaguni, are not only a hotspot for starving hammerhead sharks but it also holds the key to one of the greatest and oldest aquatic mysterious on the planet – the oddly-shaped rock formation, known as the Yonaguni Monument.

This unusual series of rock structures almost looks like an ancient stone building, designed by an architect with a badly damaged eyesight.

In reality, there are all sorts of architectural oddities, some packed with odd columns, others with a boulder sitting on a platform, as shown on fistylelife.com. But most interestingly, this Yonaguni monument also features a rock protrusion that somehow resembles a human face. Indeed, the sight of it will surely give you the creeps.

17 The Bimini Road

Situated in close proximity to an island in the Bahamas, this weird structure, known as the Bimini Road, is not only a natural oddity but is probably the greatest mystery in the area. Although it doesn’t really share the traditional definition of an actual road, this place is made up of limestone blocks running for about half a mile before it forms a rectangular and merges with the other cobblestones, fistylelife.com explains.

The most plausible explanation for this strange road would be human artifice, however, scientists were quick to refute the speculation as they consider the structure a rare product of geological processes.

16 The Vertical Pillars In The Great Lakes Region

While being out on Lake Michigan, taking sonar readings, Mark Holley, a professor of underwater archaeology, and his long-time friend, Brian Abbott, bumped into a truly spectacular object in the sea – an extraordinary array of vertical pillars that bore a striking resemblance to the world-known site, known as Stonehenge. Furthermore, the strange underwater structure happened to be sitting next to a boulder, and it seemed to carry a pretty ancient engraving of a mastodon. Interestingly, there are similar pillars in the Great Lakes region, but none happens to be stuck on the sea floor, fistylelife.com hinted.

15 Remains of the Ancient Continent Gondwana

Somewhere deep in the sea lies a spectacular array of rocks that looks like mini continents. Later on, according to thetalko.com, experts found out that the remains belonged to the ancient Gondwana continent which existed thousands of years ago. Besides, all characteristics discovered above surface land pointed to the fact that these odd rock formations were actually made of granite, sandstone, and gneiss.

The bizarre-looking remains were once part of the ancient continent, known as Gondwana. From a geographical perspective, these patches of land broke up and went down as India detached from Australia thousands of years ago.

14 Asphalt Domes Off the Coast of Santa Barbara

Back in 2007, a team of experienced scientists from the US Oceanographic Institute made an unprecedented discovery in the entire history of oceanography – they were able to discover an ancient cluster of naturally-shaped asphalt deposits off the coast of Santa Barbara. Initially, the domes were considered the product of an oil well that once swept through the seafloor; however, it was later concluded that these otherwise bizarre domes could actually support a vibrant ecosystem; therefore, it could contain fossilized remains of prehistoric animals as well. According to fistylelife.com, the deposits were discovered in the 700-foot-deep water off the coast of Santa Barbara.

13 The Lost City of Heraklion

After years and decades spent in searching, the team of Dr. Franck Goddio came across the greatest and most significant discovery they had ever made in their careers. Goddio’s team managed to uncover a whole city lying about 30 feet below the surface of Aboukir Bay.  Fitstylelife.com also details that the city was identified as Thonis or the lost city of Heracleion (named after the Greek mythical hero Hercules).

As a matter of fact, tons of other ancient artifacts, such as jewels and ship anchors, have since been found and recovered.

Even now scientists still wonder how in the world these statues ended up on the seafloor.

12 The City of Pavlopetri

In 1967, Dr. Flemming - a marine-geo archaeologist – discovered the ancient city of Pavlopetri off the coast of Laconia, Greece. The location of the city is quite remote; therefore, the city has been almost perfectly preserved. The ancient city of Pavlopetri covers a radius of 100,000 square km, and only half of that has ever been explored by researchers. According to talko.com, the discovery of Pavlopetri is also a shred of evidence for the Neolithic pottery carefully preserved inside it.

The archaeologist, Dr. Flemming, has also shared that the Neolithic pottery may even be 5000-6000 years old.

Furthermore, the trade goods and wrecks nearby also point to a possible seafaring trade in the Mediterranean.

11 A Violin On Board RMS Titanic

It might have been over a century since RMS Titanic crashed into an iceberg but divers still get to find random objects from the shipwreck. While most are quite hard to identify underwater, others are too obvious to miss, and this violin is an excellent example of that. If you’ve seen the movie, then you must remember the heart-breaking moment when all the musicians kept playing the violin while the ship was going down. Also, Titanic happens to be one of the most dramatic accidents of all time and the scale of the tragedy only contributes to its world-known fame. Over 1,200 passengers went down with Titanic, thetalko.com details, and besides the ship itself, there are still human remains and all sorts of personal belongings resting on the seafloor.

10 Odd Riverbeds On The Bottom of Black Sea

Although it’s not exactly an item that you can take home for exploration, divers were dumbfounded when they discovered multiple riverbeds on the seafloor. Of course, it’s not that unusual to see riverbeds in the sea, however, according to thetalko.com, the location was complete with its own trees lining the riverbeds. After hours of explorations, the researchers concluded that the water has got a higher saline content when compared to the surrounding seawater. Better yet, it flows on the bottom of the Black Sea. But most interestingly, there are also floodplains, raids, and waterfalls about 35 miles into the sea, waiting to be discovered as well.

9 The Ancient Kingdom of Cleopatra

Queen Cleopatra’s ruling might have long bitten the dust, but her reign still finds a way to excite the world. In fact, she happened to be the last Pharaoh of Ancient Egypt until the day when her city was utterly destroyed and sunk by a devastating earthquake and the resulting tidal waves.

In 1998, a group of divers began an exploration mission off the coast of Alexandria, Egypt resulting in over 20,000 artifacts and foundations of palaces, statues of Goddesses, and all the like. Among the odd structures that were discovered in the sea was a huge statue of Cleopatra and Julius Caesars son alongside a whole graveyard of shipwrecks that once made up her royal fleet, thetalko.com notes.

8 The Mysterious Train Graveyard

In 1985, a guy named Paul Hepler was attempting to map the sea floor, but when he dived down to 90 ft below the surface, he unwittingly discovered the final resting place for a series of sunken trains. The trains, as shown on thetalko.com as well, stretch as far back as the 1850 and the model was only around for a few years before its production was officially shut down.

The model, known as Planet Class 2-2-2 T, was considerably smaller than the rest of the trains.

For instance, model 2-2-2 T weighed around 15 tons while its fellas were at least twice as heavy.

7 The Ghost Fleet of Chuuk Lagoon

From a historical viewpoint, the Japanese Imperial Army used the Chuuk Lagoon as the site for their naval fleet; however, when the U.S army got wind of it, they attacked and eventually sank a dozen warships, lots of 32 merchant ships, and hundreds of warplanes. Back in the 90s, it was a devastating blow to Japan.

Over half a century later, though, parts of the sunken warships and planes have remained stuck on the seafloor while others were eventually discovered by divers.

All in all, thetalko.com revealed that the wrecks from the Ghost Fleet seem to be scattered all over the place in New Guinea, so there’s still much left for divers to explore.

6 The Airplane Graveyard

Somewhere off the Marshall Islands lies another ancient graveyard of WW 2 warplanes. These warplanes, according to thetalko.com, weren’t sunk by U.S forces like the previous warships in WW2 – they were merely tossed into the water by the U.S. Army when they abandoned the Marshall Islands. Among them were also the well-known B-25 Mitchell, the Gruman TBF Avenger – a hair-raising torpedo bomber – alongside other formidable warplanes that once dominated the area. For all history-lovers, this location will probably be a great place for exploration. After all, most of these ancient warplanes were used in WW2 but are now left on the sea floor in total oblivion and darkness.

5 The Ancient Phoenician Vessel

This particularly odd vessel was discovered by divers off the coast of Malta, and it most likely belonged to the Ancient Phoenician. According to thetalko.com, the relic was at least a few thousand years old when it was found. But most interestingly, the cargo it carried was somehow intact.

Among the relics were lava grinding stones, large ceramics hugs and other small objects meaning that the Ancient Phoenician vessel was used as a trading vessel at the time.

Additionally, the Phoenicians were actually quite famous for being great merchants and shipbuilders who would often sail the open seas. But unfortunately, even the most refined shipbuilding cannot withstand the whims of the sea.

4 Trucks At The Bottom of The Larnaca Bay

While finding parts of sunken ships and warplanes from WWII isn’t super odd, the sight of rusty trucks at the bottom of the Larnaca Bay certainly is. In June 1980, two large vehicles had to be transported on a ship to Cyprus; however, for some reason, the trucks went down along with the ship, known as MS Zenobia, which carried them. Today, those who want to take a close-up look at the wreck can find it at about 42 meters below the surface, thetalko.com notes. All in all, it's really amazing to know that most of these rare objects have been underwater for thousands of years before being discovered.

3 Tank And Masks - A Haunting Reminder Of The War

The sight of tank and masks underwater is quite mesmerizing, especially when you know that it’s a reminder of the war. As seen in the picture above, the so-called Nippo Maru can be found in Truk Lagoon in Micronesia, and it’s considered a pretty unique site for divers. This medium-sized freighter was loaded with some curious items for exploration, including an actual military tank, thetalko.com reveals.

As bizarre as it is, the tank sat on the port side of the ship and was discovered in June 1980 by a guy named Klaus Lindermann.

From a historical viewpoint, the ship was bombed in 1945 and is now a beautiful, yet a bit freakish sight to see. Some even call the ship a “million-dollar wreck”, which is fair given its unique looks.