The earliest known lock and key device was discovered in the ruins of Nineveh, the capital of ancient Assyria. This lock was wooden; metal keys and locks were later invented by the Romans. They substituted wood for brass and iron, making them more durable and less vulnerable to erosion. The Romans also invented wards, a technological advancement that made it so locks could only be opened by a corresponding key. This Art Deco style key necklace is too special to keep locked up.