Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Enamel is hardest substance in the human body.
61
Your heart will pump about 212 million liters in its lifetime.
26
Women have about four times as many foot problems as men; lifelong patterns of wearing high heels often are the culprit.
111
The average sperm cell swims at 8 inches per hour.
76