For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
It takes about 20 seconds for a red blood cell to circle the whole body.
102
If your DNA was stretched out it would reach to the moon 6,000 times.
256
Your thumb is about the same size as your nose.
124
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193