The human brain doesn't stop developing until about 25 years old.
102
The human body contains over a billion miles of DNA.
147
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
It takes about 20 seconds for a red blood cell to circle the whole body.
102
The average person's skin weighs twice as much as their brain.
131
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515