Mars had an oxygen-rich atmosphere around 4 billion years ago
13
Cows can sleep standing up, but they can only dream lying down.
745
It's possible to die from a broken heart; it's called Stress Cardiomyopathy.
165
Only about 2% of the world population has green eyes.
36
Some monks can increase their body temperature so much they can dry soaking sheets in a freezing room!
31
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