You can hear the blood flowing through your ears if you find a quiet place and cover them tightly.
17
There are glasses which allow a red-green color-blind person to see colors the way everyone else does.
22
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
12
Your body is creating and killing about 2.4 million red blood cells per second.
17
Blue eyes are a genetic mutation. Before the mutation occured, all humans had brown eyes.
89
All humans have the ability to see ultraviolet light, but it is passively filtered out by the eye's lens. People who undergo surgery to remove the lens can detect ultraviolet light.
21
The average person's skin weighs twice as much as their brain.
131