The focusing muscles of the eyes move around 100,000 times a day. To give your leg muscles the same workout, you would need to walk 80km (50 miles) every day.
21
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
There are glasses which allow a red-green color-blind person to see colors the way everyone else does.
22
All humans have the ability to see ultraviolet light, but it is passively filtered out by the eye's lens. People who undergo surgery to remove the lens can detect ultraviolet light.
22
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
An Indian man known as "Snake Manu" can put small snakes, including deadly cobras, into his mouth and pass them out through his nose.
59
When you get goosebumps and your hair stands, the hair helps to trap air, making you feel warmer by keeping in your body heat.
46