My grandparents saw quite a change. They lived from horse and buggy days to space satellites. Remember Sputnik? I do. It was launched by the Russians on October 4, 1957. Both my grandfathers worked on the railroad when all the engines were steam engines. One was an engineer on the Pennsylvania RR and the other was a conductor on the B&O. They both retired while the engines still ran on steam. I sure miss the sound at night of those steam locomotive whistles. Diesels are just not the same.
I would say that the biggest and quickest change happened after WW1 and ended after WW2. OK, I got to admit that I have seen a lot of change, too. I, too, remember those steam engines and the soot and dirt they produced, but loved the sound. The chug, chug, chug and then the slipping of the wheels as they started to pull a long line of rail cars. I even worked for two different rail car manufacturers. I guess railroading was in my blood.
In that period, we went from biplanes to jets. Yes, jet aircraft were in use by the end of WW2 but were in their infancy. There have been a lot of changes that happened quite quickly. Tell us what quick changes you have seen in your life time that left an impression on you and have a great day, you hear?