Your body is creating and killing about 2.4 million red blood cells per second.
17
The human body contains over a billion miles of DNA.
147
Enamel is hardest substance in the human body.
61
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
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
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
The average sperm cell swims at 8 inches per hour.
76