Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Your heart will pump about 212 million liters in its lifetime.
26
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
It takes about 20 seconds for a red blood cell to circle the whole body.
102
The human brain is very soft, having a consistency similar to soft gelatin or firm tofu.
13
If your DNA was stretched out it would reach to the moon 6,000 times.
256
The average person's skin weighs twice as much as their brain.
131
Enamel is hardest substance in the human body.
61