So I was playing a game the other night and suddenly realized that NO progress was being made in any of my cities and my research was stalled as well. I wasn't in anarchy and I didn't notice any significant event that happened. Then I noticed some small red writing right above the civ scores that said something like, "Production delayed/ceased for 12 turns." Sure enough 12 turns later everything resumed its normal pace. Anyone have any idea what caused this?