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Yonaguni Monument, Japan -

Located off the coast of Yonaguni, the southernmost of the Ryukyu Islands, this formation has been the subject of much speculation.

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Yonaguni Monument, Japan -

Discovered in 1986, some claim this tiered formation is man-made while others argue it is natural for sandstone formations in tectonic areas to develop this shape. What do you think?

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Christ of the Abyss - The original submerged bronze statue of Jesus Christ by Guido Galletti is housed in the Mediterranean Sea, off San Fruttuoso. But the statue’s family has grown since it was originally placed in 1954.

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Christ of the Abyss - Several other casts have since been placed in different parts of our big, vast ocean, of which the following two stand out. The second bronze statue was submerged off the coast of Grenada in 1961, while a third, placed in 1965, can be found in the United States off the coast of Key Largo, Florida.

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Cancún Underwater Museum, Mexico -

Known as MUSA for Museo Subacuático de Arte, this museum opened in 2010 in an effort to save the area's coral reefs by providing an alternative diving destination.

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Cancún Underwater Museum, Mexico -

The museum has about 500 art pieces, most by British sculptor Jason deCaires Taylor, but also includes the works of Mexican artists.

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'Sweepstakes' shipwreck, Canada - Located in Lake Huron in Ontario, this Canadian schooner, called 'Sweepstakes,' sank in September 1885.

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'Sweepstakes' shipwreck, Canada - This is one of the thousands of ships that sunk in the Great Lakes, most of which remain inaccessible unlike the 'Sweepstakes,' which can be visited by boat passengers, divers, and snorkelers.

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Bikini Atoll, Marshall Islands - The site of 23 nuclear tests between 1946 and 1958, Bikini Atoll opened to the public in 1996, after being deemed clear of radiation.

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Bikini Atoll, Marshall Islands - Divers interested in checking out the islands' famous shipwrecks from the post-World War II era can do so as long as they request a permit beforehand. 

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Neptune Memorial Reef, USA -

Located 3.2 miles off the coast of Key Biscayne, Florida, this artificial reef acts as an underwater graveyard.

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Neptune Memorial Reef, USA -

The remains rest protected by stone lions in this underwater city.

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Archaeological Park of Baia, Italy -

Baia served as a recreational city for the Roman elites, including figures like Nero, Cicero, and Caesar, until the 8th century—a Roman-era Las Vegas, if you will.

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Archaeological Park of Baia, Italy - But the city was sacked by the Saracens in the 8th century, and by 1500 the place was in ruins. Due to volcanic activity in the area that caused water levels to rise, the ruins are now largely underwater.  Local authorities opened the site for diving activities in 2007.

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Chuuk Lagoon, Micronesia - Previously known as Truk Lagoon, this site is a must-see for wreck enthusiasts. As Japan's main base during World War II, the lagoon housed the country's fleet during the conflict, the skeletons of which can be seen scattered across its bottom.

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Chuuk Lagoon, Micronesia - The sight is a result of an attack by the United States in February 1944—known as Operation Hailstone—which turned the lagoon into "the biggest graveyard of ships in the world," according to The New York Times.

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Dos Ojos, Mexico - Officially Sistema Dos Ojos, this extravagant diving site in Tulum, in the Yucatán Peninsula, houses the deepest known underwater cave passage at 387 feet (118 meters), according to cenotesmexico.org.

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Dos Ojos, Mexico - This incredible underwater cave system was featured in 'Journey Into Amazing Caves' (2001), and in the BBC/Discovery Channel series 'Planet Earth' (2006).

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Molinere Underwater Sculpture Park, Grenada - Located off the west coast of Grenada, this ecological project intended to create new places for corals and other marine life to grow in efforts to conserve the local reefs, is the first of its kind.

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Weeki Wachee Mermaid Show, United States -

For six decades, the mermaids of Weeki Wachee have been performing feats underwater to entertain curious visitors.

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Weeki Wachee Mermaid Show, United States -

The show takes place monthly at the Weeki Wachee Springs State Park, located in Hernando County, on Florida's northern Suncoast.

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The Green Lake, Austria - Located in a village named Tragöß, the lake functions as a regular park in the fall and a diving attraction in the spring.

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The Green Lake, Austria -

This is because the park fills up with snowmelt from the surroundings as temperatures rise with the changing seasons.

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Silfra fissure, Iceland - Divers seeking to swim between two continental plates need look no further than the Þingvallavatn Lake, located in the Þingvellir National Park.

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Silfra fissure, Iceland - This rift, which is widening about 0.8 inches (two centimeters) a year, marks the spot where the Eurasian and North American plates meet.

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Amphitrite statue, Cayman Islands -

Located almost 55 feet (27 meters) below water, this mermaid statue off Grand Cayman Island is by Canadian sculptor and diver Simon Morris. Named after the wife of Poseidon in Greek Mythology, the statue is almost nine foot (2.7 meters) and weighs more than 595 pounds (270 kilograms.)

See also: The radioactive animals of Chernobyl

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