Knap of Howar

The Knap of Howar () on the island of Papa Westray in Orkney, Scotland is a Neolithic farmstead which may be the oldest preserved stone house in northern Europe. Radiocarbon dating shows that it was occupied from 3700 BC to 2800 BC, earlier than the similar houses in the settlement at Skara Brae on the Orkney Mainland.

Source: Wikipedia