The oldest stone tools found are dated from 2.7 - 2.9 million years ago. The species that made these tools is unknown.
13
Mushrooms are more closely related to humans than they are to plants.
47
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
The human body contains over a billion miles of DNA.
147
The world's shortest man measures only 21.5 inches.
73
You can't tickle yourself.
29