Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
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
Your heart will pump about 212 million liters in its lifetime.
26
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
An Indian man known as "Snake Manu" can put small snakes, including deadly cobras, into his mouth and pass them out through his nose.
59
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
The human body contains over a billion miles of DNA.
147
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266