Do you know how a key opens a lock? A Norwegian animator Stian Berg Larsen created a wonderful 3D animated video below shows exactly what happens when you insert a key in a lock and then give it a turn. The video animation shows a so-called pin-tumbler lock, in which small pins line up with grooves in a key before the key can turn.
The modern pin-tumbler lock and flat key, invented by Linus Yale Jr. and patented in 1861, was inspired by locks linked to ancient Egypt.