The oldest wheel in the world is the Ljubljana Marshes Wheel, which was discovered in 2002 near Ljubljana, Slovenia. It is dated to around 3,150 BCE, which makes it about 5,170 years old. It was found in a prehistoric settlement of pile dwellings, which are houses built on stilts in the marshes.
The wheel was made of ash and oak wood, and was part of a two-wheel cart. It shows that wooden wheels may have appeared almost simultaneously in Mesopotamia and Europe, though finds of actual wheels from Mesopotamia date from significantly later. The Ljubljana Marshes Wheel is a remarkable example of ancient craftsmanship and technology.