Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Your thumb is about the same size as your nose.
124
Your heart will pump about 212 million liters in its lifetime.
26
The human brain has the capacity to store everything that you experience.
4k
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Enamel is hardest substance in the human body.
61
Yawns are more contagious among people with closer relationships.
163