It takes about 20 seconds for a red blood cell to circle the whole body.
102
Unconsciousness will occur after 8-10 seconds after loss of blood supply to the brain.
93
You can't tickle yourself.
29
An unprotected human can survive up to 1.5 minutes in space with no permanent bodily damage.
82
When you kiss someone for the first time, you get a spike in the neurotransmitter dopamine, making you crave more.
23
The oldest stone tools found are dated from 2.7 - 2.9 million years ago. The species that made these tools is unknown.
13
A person can live without food for about a month, but only about a week without water.
156
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118