At least one year in that range where something happened.

IDK, man, the '70s sounded pretty wild: https://status451.com/2017/01/20/days-of-rage/

Which is why I wrote "1975" and not "1970" or "1972".

Like if nothing happened a day exactly 24 years ago...

1975-1988 we lived in the Cold War and the potential of nuclear strikes. The African, gay and trans communities (in particular but not exclusively) dealt with the AIDS epidemic. Iran moved to theocracy. In the 90s, we had the Iraq war that was not bad for the US but massively destabilized the region. In the 2000s we had 9/11 and let's not understate the fear from the Muslim community here. Africa has lived through famine and the pains of decolonization after their wealth was stripped and stolen over centuries.

This is worse, but we have always lived in "interesting times" depending on where you were in the globe.

I was restricting my imaginings to internal unrest because that is what caused most of the death and suffering historically in China.

I'd say that nothing since the collapse of the USSR has been as existentially threatening as the Cold War.