Your thumb is about the same size as your nose.
124
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
The human brain doesn't stop developing until about 25 years old.
102
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Your heart will pump about 212 million liters in its lifetime.
26
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
If your DNA was stretched out it would reach to the moon 6,000 times.
256
The largest cell in the human body is the female egg and the smallest is the male sperm.
682