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
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
It took 200,000 years for humans to reach 3 billion in number. It took 40 years for the next 3 billion.
11
The human brain is very soft, having a consistency similar to soft gelatin or firm tofu.
13
Your heart will pump about 212 million liters in its lifetime.
26
In 30 minutes, the average body gives off enough heat (combined) to bring a half gallon of water to boil.
198
Your thumb is about the same size as your nose.
124