The right lung is slightly larger than the left. See more

To "testify" was based on men in the Roman court swearing to a statement made by swearing on their testicles. See more

Former enemies, America and Russia now have a great deal in common - they both lead the world in locking people up. See more

When baby sharks are born, they swim away from their mothers right away and are on there own. In fact, their mothers might see them as prey. See more

Those stars and colours you see when you rub your eyes are called phosphenes. See more

Women blink nearly twice as much as men. See more

Male lions can sleep for up to 20 hours a day. See more

A rat can fall from a five story building without injury. See more

There are 100 million internet users in China. Some of the sites they can't access are BBC news, Amnesty International and Dalailama.com. See more