The oldest stone tools found are dated from 2.7 - 2.9 million years ago. The species that made these tools is unknown.
13
Cows can sleep standing up, but they can only dream lying down.
745
Your body is creating and killing about 2.4 million red blood cells per second.
17
There are so many kinds of apples that if you ate a new one everyday, it would take over 20 years to try them all.
34
The 409 escalators in the London subway cover a distance every week which is approximately equivalent to several trips around the globe!
94
The focusing muscles of the eyes move around 100,000 times a day. To give your leg muscles the same workout, you would need to walk 80km (50 miles) every day.
21