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
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
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
Every year your body replaces 98% of your atoms.
119
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
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