The right answer is cities
The Treaty Of Versailles placed restrictions on how strong Germany could build its military and took away large portions of land that were taken during WW1. Loosing Lot of land right after obtaining it would make many citizens rather upset.
One incident would definitely be during the cold war more specifically during The Bay Of Pigs
another would be during a false alarm in which we thought Russia had fired nuclear weapons at us and refrained from firing back before being sure
It lead straight to lots of homeless because of lack of houseing, I hope this helps out!!!