There is no contest. It’s the wheel. From prehistoric carts to roller-coasters and rockets, the wheel is one of those inventions that is never going to be obsolete. The reason? The wheel is the mathematically optimal shape for minimizing the amount of contact with other surfaces, leading to minimal friction and thus minimal energy loss. This characteristic also makes it ideal for smooth, repetitive action without grinding it down. Exactly when and who first spotted these advantages, that no one is sure of, but it seems that the wheel was a much later invention than people generally think. Caveman would not have been able to make one, let alone work out what to do with it.
The earliest evidence archeologists have been able to find of vehicles with wheels is from Mesopotamia (Iraq) which may date as far back as 6,000 years ago. The oldest pyramid, whose construction begun about 1,400 years later, may also have benefited from the use of logs to roll the colossal stones from quarries many kilometers away.
For carts, working wheels in the early days were made of joined wooden planks cut into circular shapes. (See image above.) The first spoked wheels, introduced in Mesopotamia around 2000 BC, brought in a revolution in lightness and efficiency.
When scientists at AT&T laboratory wanted to demonstrate some of the world’s first mechanical devices in 1989, what did they choose to make? Three tiny toothed wheels, obviously!