A useful tool for measuring distance traveled, the odometer is believed to have been invented by an ancient Roman named Vitruvius. Mainly remembered as an architect, he came up with the idea for what he called a hodometer in the first century B.C. The word hodometer is derived from the Greek words for “way” and “measure.” He wrote extensively about the design, explaining how a wheel with 400 teeth would be turned by a single-toothed gear attached to the main wheel. A stone would then be dropped into a box, indicating that a Roman mile had just been traveled.However, some archaeologists maintain that such a design would have been impossible for the Romans to actually manufacture, given their inexperience with metalworking. Even Leonardo da Vinci was unable to recreate Vitruvius’s invention. More recently, Andre Sleeswyck, writing for Scientific American, reported that he was able to reconstruct it successfully.