Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Your thumb is about the same size as your nose.
124
Our Right Lungs takes more air than our left lung.
194
All the chemicals in a human body combined are worth about 6.25 euro (if sold separately).
266
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
The human brain doesn't stop developing until about 25 years old.
102