Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
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
Your thumb is about the same size as your nose.
124
All the chemicals in a human body combined are worth about 6.25 euro (if sold separately).
266
Yawns are more contagious among people with closer relationships.
163
When you take a step, you are using up to 200 muscles.
886
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127