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 sigh acts as a physiological reset button.
23
The world's shortest man measures only 21.5 inches.
73
A third of the human population sneezes when they look at the Sun. Light can signal the ocular nerve near the sinuses and triggers a sneeze.
18
The oldest stone tools found are dated from 2.7 - 2.9 million years ago. The species that made these tools is unknown.
13
Babies crawl an average of 200m a day.
212
The human brain doesn't stop developing until about 25 years old.
102
Unconsciousness will occur after 8-10 seconds after loss of blood supply to the brain.
93