Technology in the 20/21st centuries

Ahead of time, I apologize for the lameness of this question.

But what do you think has been the most influential innovation or invention in the 20th/21st centuries?

Also, what do you think are the far-reaching consequences of that invention/innovation?

The personal computer. Without the device that we are typing on right now, this forum wouldn't exist, and we wouldn't be having this discussion!

The transistor. Without it: no microchips, no microcomputers, no PCs, no Internet, no forum