Locks

The idea of the lock probably appeared independently in different parts of the world. The ancient Chinese had simple locks that could be undone with a sickle-shaped or hook-like key. Locks like this existed in China at least 4,000 years ago, and probably earlier.

The people of ancient Egypt also protected their possessions with locks during the same period. These were slightly more sophisticated than the Chinese locks. Egyptian locks contained a series of pins of different lengths that corresponded to pegs that stuck out of the side of the key. Only a key with pegs of the right length would fit a particular lock. Unlike modern locks, which are made of hard metal, Egyptian locks were made of wood.