The human brain doesn't stop developing until about 25 years old.
102
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
When you get goosebumps and your hair stands, the hair helps to trap air, making you feel warmer by keeping in your body heat.
46
Your heart will pump about 212 million liters in its lifetime.
26
When you take a step, you are using up to 200 muscles.
886
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
It takes about 20 seconds for a red blood cell to circle the whole body.
102