I remember when New York fell. No one believed it would happen, but without power the backup generators ran for a few days and then the pumps stopped. Within a day the underground had flooded, shortly after the streets began to buckle, then the buildings.
No one could believe that a whole city could collapse, but I saw it. I watched as the cracks reached up through buildings, and then with a final groan, pulled them to the ground. I don’t know how many undead died, but I know a lot of living were still there, hiding in fear. At least they don’t have anything to fear any more.