Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217
Your thumb is about the same size as your nose.
124
Yawns are more contagious among people with closer relationships.
163
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
The human brain uses approximately as much energy as a 10 watt light bulb.
120
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118