The largest living animal by volume is the blue whale at up to 173 metric tons.

The submarine cable enabled intercontinental communication.

Some bacteria can survive in extreme environments such as deep-sea vents.

Penguins have excellent underwater vision.

Dogs can smell certain diseases such as cancer.

Some deep-sea octopuses brood their eggs for years.

Honey does not spoil when stored properly in a sealed container.

The Mariana Trench is so deep that Mount Everest could be placed inside it and still be covered by over a mile of water.

Penguins use their flippers to propel themselves underwater.