It is not possible to tickle yourself. The cerebellum, a part of the brain, warns the rest of the brain that you are about to tickle yourself. Since your brain knows this, it ignores the resulting sensation.

Spiked and studded dog-collars derive from the days of the Ancient Greeks, who would give their sheep-dogs sharply spiked collars to protect their necks from wolves whilst they watched over a Sheppard's flock at night.

The stage were the television sitcom "Friends" is shot on is said to be haunted.

AMAZING FACTS