One common explanation traces the phenomenon to ancient pagan cultures such as the Celts, who believed that spirits and gods resided in trees. Knocking on tree trunks may have served to rouse the spirits and call on their protection, but it could have also been a way of showing gratitude for a stroke of good luck.

Why do we knock on a door?

While we hope that no one tries to break into your home, a common tactic burglars use is to knock on someone's door to see if anyone is there before entering. However, even if someone isn't trying to break into your home, they could be under the influence of drugs or alcohol, which can be just as dangerous.

Where did the saying knock down ginger come from?

The name Knock-Down Ginger is thought to have derived from an old English poem about the game which reads: "Ginger, Ginger broke a winder. Hit the winda – crack! "The baker came out to give 'im a clout.