Although we generally deal exclusively with digital keys around here, this collection of keys spanning the last 3,000 years is a fascinating stroll through the history of locks, privacy, and the status that went with holding a key.
Over at Slate they have a gallery of keys reaching from the Roman empire all the way to the present with descriptions of each. The photo seen here is a Roman key:
In Ancient Rome, having keys—or anything worth locking up—was uncommon. So the key was as much a status symbol as a security device. Affluent Romans often kept their valuables in secure boxes within their households, and wore the keys as rings on their fingers. The practice had two benefits: It kept the key handy at all times, while signaling that the wearer was wealthy and important enough to have money and jewelry worth securing.
Hit up the link below for the full gallery which features keys from around the world.