It took 200,000 years for humans to reach 3 billion in number. It took 40 years for the next 3 billion.
11
A human brain produces as many as 12,000 to 50,000 thoughts per day, depending on how deep a thinker a person is.
23
If Earth's life was compressed into 1 year, then humans would have been around for only 2 seconds.
15
Pain occurs when sounds are above 130 db.
123
Blue eyes are a genetic mutation. Before the mutation occured, all humans had brown eyes.
89
A person will create enough saliva to fill two average size swimming pools during his lifetime.
191
It has been scientifically proven that stroking a cat can lower one's blood pressure!
456
On average, there's 100 billion neurons in the human brain.
83