Murder-hole

A murder-hole is a small hole in the roof or wall of a building that was used a long time ago to defend it from invaders. Back then, when people were trying to attack a castle or a fort, soldiers would pour things like boiling water, hot oil, or just throw rocks down these holes to stop the attackers from coming in. It was called a murder-hole because it was very dangerous for the attackers, who could get seriously hurt or even killed. Today, we don't really use murder-holes anymore as they are not very practical or safe.