Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The average sperm cell swims at 8 inches per hour.
76
All the chemicals in a human body combined are worth about 6.25 euro (if sold separately).
266
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
The human brain doesn't stop developing until about 25 years old.
102
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
It takes about 20 seconds for a red blood cell to circle the whole body.
102