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
An unprotected human can survive up to 1.5 minutes in space with no permanent bodily damage.
82
In Georgia, there is an airtight room called the Crypt of Civilization that was sealed in 1940. It contains numerous artefacts documenting what life was like at the time of sealing, and is scheduled to be opened in the year 8113 to show people of the future exactly what life was like.
13
You forget 90% of your dreams.
256
Mars had an oxygen-rich atmosphere around 4 billion years ago
13