Only answer if you
whick world war do you think was the defining event of the 20th century and

It was World War 2 because during that war, they made powerful bombs, and items that need special technology. When the war ended, we needed more powerful war items, so to help us make them, we invented the computer to use it as a blue print when making the weapons, mechanical items, such as robot arms, to place details into certain area's.

Hope this helps. :)

(I could give you a super long answer, but I shortened it down)

If you were to ask me, I would say World War II. That is because it was a MAJOR turning point in history and the development of technology. New bombs were made, along with new artillery equipment. New tactics and strategies were also made. If it weren't for World War II, we'd probably have less advanced technology now. 

Hope I helped! <3