About 71% of Earth's surface is covered by water, but 97.5% of that is saltwater.

The Dead Sea is so salty that you can float on its surface without swimming — it's almost impossible to sink.

Prehistoric oceans had different currents than today.

The anglerfish uses a bioluminescent lure to attract prey in the dark ocean depths.

The Earth's oceans cover more than 70% of the planet's surface.

The giant amphipod thrives in extreme ocean depths.

The Pacific Ocean contains numerous coral atolls.

There are underwater lakes on Earth.

Dolphins have been observed surfing ocean waves purely for fun — one of the clearest signs of play in non-human animals.