The wheel is one of the most famous inventions. This technology not only made it easier to travel, but also served as the base for other technologies.
But the wheel is not very old. The oldest known wheel is from Mesopotamia and was created around 3500 BC. Inventors were the Sumerian people, who inserted rotating axles into discs of wood. It was only in 2000 BC that the discs began to be hollowed out to make a lighter wheel. By that time, humans were already casting metal alloys, constructing canals and sailboats, and even designing complex musical instruments.

In fact, the main invention was not the wheel itself, which was likely invented the first time someone saw a rock rolling along, but the combination of a wheel and a fixed axle, which allows the wheel to be connected to a stable platform. Without the fixed axel, the wheel has only very limited utility.