In China, teachers allow children to sleep in class for around 20 minutes to help improve their learning.
13
A koi fish, named "Hanako", was owned by several individuals over many years and lived to be 226 years old, dying in 1977.
6
Scientists have revived a flowering plant from a fruit stored away in permafrost by Arctic ground squirrel 32,000 years ago.
16
In 1916, a US amendment was proposed to put all acts of war to a national vote. If you voted yes you would have to register as a volunteer for service in the United States Army.
5
Elephants are among the most emotional creatures in the world - they have even been known to rescue other animals, such as trapped dogs.
25
Billions of neutrinos pass unnoticed through your body every second.
6