Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
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
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
The average person's skin weighs twice as much as their brain.
131
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118