When was the wheel invented?

               The invention of the wheel must be the most iconic invention of all time, as it paved the way for so much development in the world.

               The first form of the wheel was made during the late Neolithic. Early wheels were simple wooden disks with a hole for the axle. However, the first wheel closer in appearance to the modern day one, was made in Sumeria around 3500 BC.

               Researchers have found that almost during the same period of time in Uruk in Mesopotamia, sledges were attached to four wheels to use in different terrains. The evolution of the modern day wheel was a very slow process. In 200 BC, in North Africa, wheels with teeth or cogs around their edges were used to pull water from wells.

               In the 4th century BC, the Greek philosopher Aristotle mentioned something similar to gears, when he designed devices for various construction jobs.

Picture credit: google