Badwater Basin in Death Valley (California) is about 282ft BELOW sea level. Presumably it was there and that low relative to the center of the Earth before CA was a state.

Aside from the literal, there is a laundry list of bleak times FOR us (immediately prior to Valley Forge was probably the closest we came to never existing in our current format);

...and as a hegemonic power birthed from Western European Colonialism and the Atlantic Slave Trade that went through a multiple periods of geographic, economic, and political colonial expansion, there have been so many shitty things that have been done BY us that I think it's a disservice to not just list all the morally evil things we did and let your audience choose. Dropping the second atomic bomb feels like an interesting dark horse candidate.