Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The average sperm cell swims at 8 inches per hour.
76
An Indian man known as "Snake Manu" can put small snakes, including deadly cobras, into his mouth and pass them out through his nose.
59
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
There are times when you're walking that the pressure on your feet exceeds your body weight, and when you're running, it can be three or four times your weight.
62
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197