In my lifetime, the integrated circuit and its development ecosystem, Moore's Law, and for a long while, Dennard Scaling (https://en.wikipedia.org/wiki/Dennard_

In my lifetime, the integrated circuit and its development ecosystem, Moore's Law, and for a long while, Dennard Scaling (https://en.wikipedia.org/wiki/Dennard_scaling https://en.wikipedia.org/wiki/Dennard_scaling), I think. Some others cite things like the web or the personal computer, but that would never have become a big thing without ever denser and for a long while faster ICs, then again, they don't have to be too much younger than me for the invention of the IC to fall out of their range. 9/11 was and remains big, but I don't think it's of a fraction the magnitude, unless, again, these other things happened before you were born. E.g. in that category, the assassination of JFK and how that shaped the coming Vietnam War was a much bigger thing for the US, not sure about the world outside of East Asia, though, except through the profound effects it had through changing the US. In a few years I might list Watergate in that category, for how it changed the power balance between the Executive and the Congress, and among other things changed the budgeting system to one where all internal restraints are pretty much gone. When the Feds can no longer can borrow huge sums of money at around 0% interest rates, well, things will get very interesting in the "interesting times" sense. How that will effect those outside the US, though, I'm not sure, but nothing good, I would think. I.e. the 2nd bank collapse phase of the Great Depression on steroids sort of magnitude.