Phlegreian Fields erupt

Phlegreian Fields supervolcano erupts, decimating Europe.

It is unknown if the Phlegreian Fields supervolcano in Italy was somehow destabilized by the Yellowstone eruption. It could as well just be a coincidence. Whatever the case, the second supervolcano eruption happened - and changed everything. Naples was wiped rom the map. Italy was de facto destroyed and collapsed into several almost post-apocalyptic nations.   But it had other, more regional or even global effects. It decimated Southern Europe. The chain of economic collapses struck European Union, essentially kicking it out from importance. That, in turn, even worsened the global economic disaster that the United States destruction was. Markets dived, much worse than during all past crisis of the 20th and 21st Centuries.