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 doesn't stop developing until about 25 years old.
102
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
If your DNA was stretched out it would reach to the moon 6,000 times.
256
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92