In the average lifetime a person will breath in about 44 pounds of dust.
21
Your skeleton keeps growing until you are about 35, then you start to shrink.
74
Every hour one billion cells in the body must be replaced.
17
The focusing muscles of the eyes move around 100,000 times a day. To give your leg muscles the same workout, you would need to walk 80km (50 miles) every day.
21
The average person's skin weighs twice as much as their brain.
131
Human thigh bones are stronger than concrete!
63
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Your body is creating and killing about 2.4 million red blood cells per second.
17