Enamel is hardest substance in the human body.
61
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
The human body contains over a billion miles of DNA.
147
When you get goosebumps and your hair stands, the hair helps to trap air, making you feel warmer by keeping in your body heat.
46
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197