I came across this very nice exploration of numerous instances in the past and also very recently, when big ideas were proposed that people thought could not and would not happen, only to be proved wrong when later it became inevitable and was done. Landing on the moon, landing on a comet are but two examples. Produced by Toyota.
It reminded me of an old saying of Dr. Ed Lindaman, program planner for Apollo:
Everything possible today was at one time impossible. Everything impossible today may at some time in the future be possible.