There are many abandoned villages, towns, and even cities in the River Kingdoms — the homes of petty lords who were burnt out of their holdings and put to flight. Some of these are little more than a clearing in the forest, while others, such as Heibarr and Cordelon, have entire walls and heaps of cracked stone to show where a fortification once stood. The largest of these is Nystra, a city of humans who learned the trick of growing silkworms, either by stealing it from the Zho or mastering the art themselves. It is said that one night, a thousand black-clad demons descended on the city howling for blood and slaying all within it. That might be a bardic tale told once too often and inflated in the telling, but silk no longer comes from Nystra, and its hilltop citadel is a jumbled ruin slowly collapsing down the slope.
Sources: Pathfinder Chronicles Campaign Setting