Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
If your DNA was stretched out it would reach to the moon 6,000 times.
256
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
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
Every year your body replaces 98% of your atoms.
119
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
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