More than a dozen men have stood on the surface of the moon, but only three have been to Challenger Deep in the Marianas Trench, the deepest known spot in the ocean.
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There are approximately three million shipwrecks on the ocean floor, worth billions in value and treasure.
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Sea otters hold hands while sleeping so they don’t drift away from each other.
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The Caspian Sea is also classed as the world's largest lake.
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Sharks, like other fish, have their reproductive organs in their chests.
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In 1992, 29,000 rubber ducks washed off a ship. They were found thousands of miles away 8 years later.
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There was once an undersea post office in the Bahamas.
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