Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The human brain uses approximately as much energy as a 10 watt light bulb.
120
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
All the chemicals in a human body combined are worth about 6.25 euro (if sold separately).
266
Your heart will pump about 212 million liters in its lifetime.
26
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Your thumb is about the same size as your nose.
124
An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
73