The Caspian Sea is also classed as the world's largest lake.
52
Tidal forces between the Earth and Moon are slowing the Earth down and pushing the Moon further away.
46
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
Sea otters hold hands while sleeping so they don’t drift away from each other.
104
The North Atlantic gets 2.5 centimetres (1in) wider every year.
119
Sharks, like other fish, have their reproductive organs in their chests.
248
Two dogs were among the Titanic survivors.
262
There was once an undersea post office in the Bahamas.
241