It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
The world's shortest man measures only 21.5 inches.
73
Modern humans first appeared about 200,000 years ago, but record keeping didn't begin until about 6,000 years ago. That means about 97% of human history is lost.
21
If the human eye was a digital camera, it would have 576 megapixels.
25
You can't tickle yourself.
29
Your heart will pump about 212 million liters in its lifetime.
26
After age 30, the brain shrinks a quarter of a percent (0.25%) in mass each year.
139
An unprotected human can survive up to 1.5 minutes in space with no permanent bodily damage.
82