It took 200,000 years for humans to reach 3 billion in number. It took 40 years for the next 3 billion.
11
Enamel is hardest substance in the human body.
61
An unprotected human can survive up to 1.5 minutes in space with no permanent bodily damage.
82
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
Crying literally alleviates stress and uniquely allows humans to decrease feelings of anger and sadness.
24
Some monks can increase their body temperature so much they can dry soaking sheets in a freezing room!
31
The human brain has the capacity to store everything that you experience.
4k
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118