Gentoo penguins give pebbles to the penguin they want as a mate.

Koalas sleep up to 20 hours a day.

Mars has the tallest volcano in the solar system, called Olympus Mons.

Uranus spins on its side, like a rolling ball.

Your fingernails grow faster than your toenails.

A bolt of lightning is about five times hotter than the surface of the Sun.

The Amazon rainforest is home to about one in ten of all known kinds of animals.