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
Only about 2% of the world population has green eyes.
36
Mars had an oxygen-rich atmosphere around 4 billion years ago
13
The University of Oxford (teaching since 1096) predates the Aztec empire (1428 - 1521).
14
Cows can sleep standing up, but they can only dream lying down.
745
Your thumb is about the same size as your nose.
124