I strongly disagree and thought I'd ask the general community what they think is most significant in our collective lifetime.
As for myself, I wasn't alive then, so it's probably the attacks on September 11th. They resulted in numerous wars, changed the lives of probably billions of people, changed the characterization of an entire religion, affected foreign and domestic policies, etc.
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.
1. End of Cold War / The Fall of the Soviet Union / Berlin Wall - because of its massive impact on geopolitics, the ultimate failure of the communism experiment, as pertains to Germany, the reunification of East and West.
2. The Invention of the WWW - this was the ultimate culmination of the information revolution, the 20th centuries version of the industrial revolution.
3. The Maastricht Treaty / Introduction of Euro - Formation of the European Union as we know it today. For western culture this has had and will continue to have profound impact whether the union ultimately succeeds in becoming a USA 2.0 or disintegrates into an economic union (Brexit, Grexit, etc).
4. 9/11 - For what it represents for the 21st century, as regards a global jihad, an ongoing terrorism and counter-terrorism war, and what will most likely become the largest issue of at least the first half of the 21st century.
5. The introduction of "Socialism with Chinese Characteristics" starting in 1978 (combined with the post-Tienanmen crackdown, which appears to have been largely responsible for cementing the CP's longevity).
6. Putin's appointment as Prime Minister on December 31, 1999 (and the ensuing waves of influence which have not only swept the region... but indeed, with the last election, have significantly impacted politics in the U.S. itself).
7. The Reagan/Thatcher elections in 1979 / 1980 (basically responsible for the rise of neoliberalism as we know it).
8. The Iranian revolution of 1979.
9. The onset of the global HIV epidemic (ultimately leading to far broader recognition of LGBTQ rights, and to loosening of mores with regard to non-reproductive sex in general).
We have to stop somewhere, so 1978-1979 seems about as good as anywhere. (Basically, nearly everyone here seems to be "post-Vietnam/Watergate" and "post-deindustrialization").
Other significant changes have had no specific turning point:
1. Major decrease in global poverty.
2. Major decrease in urban crime in the U.S (largely responsible for gentrification and the long-scale housing bubbles we have today), for reasons still not entirely understood.
3. Gradual winding down of armed conflicts in Latin America.
4. And of course, anthropomorphic climate change.
Now on to your explicit question; By far and away the most significant turning point in our lifetimes is (last century) Ayn Rand's validation of reason by solving the problem of universals in her theory of concepts. I don't expect anyone here reading this to understand or appreciate this but it is an epic, world-changing achievement and, like Aristotle, she will be discussed in the history books 1000's years from now. She is a turning point in the history of man.
It's pretty safe to say that if no one on HN knows what the hell you're talking about (and not even WP mentions PoS and AR in association with each other), then no, it's not likely that this will be seen as "the most significant turning point" of our era, centuries from now.
Over my head, care to define your abbreviations? Thanks
PoS = should be PoU = Problem of Universals
AR = The Greatest Thinker Of Our Lifetime, And Indeed, One of The Greatest Thinkers In The History Of Man
Don't forget Aristotle! Everything we have now including science, technology, medicine, math, freedom and even Ayn Rand we owe to him for discovering the laws of deductive logic. But deductive logic was not validated till Rand identified the principle behind concept formation.
So he was elected by Leftists?
I think it's more he was repudiated by the GOPe(stablishment) and most of the Established Authorities (i.e. press) that claims to be of the "Right". We on the Alt Right beg to differ as to their being very much at all on the right.
Ultimately we will get communism or fascism and how or who are just historical details. Rand showed these are just different expressions of collectivist ethics which is driving politics. But ethics is not a primary -- it derives from epistemology, which is why validating reason last century was a major turning point in Western thought and the OP's question.
Also outside the US there is a huge rural to urban migration occurring.
Notably in 2009 the world's population was majority urban for the first time in human history. It is now more common to live in a city than not to.
https://www.theguardian.com/technology/2010/aug/29/my-bright...
2) 9/11. It created policies that we deal with still, implanted ideology and its critics, and likely emboldened future attacks.