of pottery, but it was the use of the wheel as a transformer of energy (through water wheels, windmills, and even treadmills) that revolutionized the application of nonhuman power sources. The first two-wheeled carts were derived from travois and were first used in Mesopotamia and Iran in around 3,000 BCE.

The oldest known constructed roadways are the stone-paved streets of the city-state of Ur, dating to , and timber roads leading through