People used to believe that ancient peoples built their towns on top of mounds. Then it was realized that the mounds rose up under the towns due to garbage being discarded and building up under the town. Over the centuries ancient communities were elevated in this way, sometimes by dozens of yards. The ancient cottages of this village are slowly sinking under the rising level of the roads and surrounding land. There is no way to raise them, so they accurately show how the ground is building up over time. It's up at least three or four feet since the cottages were first constructed.