Wheel and Axle - The Powerful Simple Machine

There are very few innovations in mechanical engineering that have had as much influence as the wheel. The modern world would look very different without them.

Wheels, technically the wheel and axle is one of the six simple machines as defined in antiquity and expanded during the Renaissance.
The first depictions of wheeled-vehicles appear on an earthenware Bronocice pot from Poland and dates to around 4000 BCThe pot clearly depicts a wagon of some kind with four wheels set on two axles.
The earliest actual evidence of a physical wheel-axle combination comes from Slovenia and is dated to around 3360-3030 BC.
Wheels literally changed the world and have been a constant feature of human transport devices the world over.