There was once an undersea post office in the Bahamas.
241
The Caspian Sea is also classed as the world's largest lake.
52
In 1992, 29,000 rubber ducks washed off a ship. They were found thousands of miles away 8 years later.
707
NYC's Metropolitan Transit Authority (MTA) dumps old subway cars into the ocean to serve as artificial reef.
8
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.
17
There are approximately three million shipwrecks on the ocean floor, worth billions in value and treasure.
22
There are approximately three million shipwrecks on the ocean floor, worth billions in value and treasure.
22