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.
21
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
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
The average sperm cell swims at 8 inches per hour.
76
The human brain doesn't stop developing until about 25 years old.
102
Blue eyes are a genetic mutation. Before the mutation occured, all humans had brown eyes.
89
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
The brain receives 20% of the body’s oxygen and 25% of total body glucose utilization, despite it accounting for only 2% of a person’s weight (about 1.4 kilograms).
8