For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Enamel is hardest substance in the human body.
61
The average sperm cell swims at 8 inches per hour.
76
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
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
The average person's skin weighs twice as much as their brain.
131