Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Yawns are more contagious among people with closer relationships.
163
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
The human brain has the capacity to store everything that you experience.
4k
Your body is creating and killing about 2.4 million red blood cells per second.
17
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
When you take a step, you are using up to 200 muscles.
886