On average, there's 100 billion neurons in the human brain.
83
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Enamel is hardest substance in the human body.
61
The average person's skin weighs twice as much as their brain.
131
Tigers can see 6 times better at night than humans.
305
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
There are times when you're walking that the pressure on your feet exceeds your body weight, and when you're running, it can be three or four times your weight.
62
You forget 90% of your dreams.
256