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
The average sperm cell swims at 8 inches per hour.
76
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217
Every year your body replaces 98% of your atoms.
119
If your DNA was stretched out it would reach to the moon 6,000 times.
256
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266