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
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 human body contains over a billion miles of DNA.
147
Your body is creating and killing about 2.4 million red blood cells per second.
17
The average person's skin weighs twice as much as their brain.
131
Every year your body replaces 98% of your atoms.
119
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22