Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The human brain has the capacity to store everything that you experience.
4k
Every year your body replaces 98% of your atoms.
119
It takes about 20 seconds for a red blood cell to circle the whole body.
102
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
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
One human hair can support 3 ounces.
191