Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The average person's skin weighs twice as much as their brain.
131
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
Your heart will pump about 212 million liters in its lifetime.
26
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
The human brain doesn't stop developing until about 25 years old.
102