For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Your heart will pump about 212 million liters in its lifetime.
26
The human brain uses approximately as much energy as a 10 watt light bulb.
120
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
Your thumb is about the same size as your nose.
124
If your DNA was stretched out it would reach to the moon 6,000 times.
256
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18