The bark of an older redwood tree is fireproof.
65
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
Forensic scientists can determine a person's sex, age, and race by examining a single strand of hair.
101
0.3% of solar energy from the Sahara is enough to power the whole of Europe.
310
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
Stephen Hawking once tried to find potential time travellers by throwing a party and only sending out invitations after the party.
17
The most expensive material on the planet is antimatter - worth $62.5 trillion per gram.
18