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
An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
73
If your DNA was stretched out it would reach to the moon 6,000 times.
256
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118