Skara Brae Neolithic Village is about 5,000 years old (it was occupied from c3100 BC to c2500 BC) and is one of the earliest known farming villages in Britain. It is sited on the west coast of Mainland, Orkney close to the beach of the Bay of Skaill although it would originally have been much further back from the coast. It consists of a closely knit arrangement of 6 houses linked by passages, with a single separate detached workshop. The remains of the village survived to the present day because the houses were built into a large mound of midden material which helped to protect the structure and, following its abandonment, the site was filled and covered by sand dunes. The village was first discovered following a storm in the winter of 1850 when it was partially exposed and the laird of Skaill, William Watt, began exploration of the site. Modern archaeological excavation began with the work of Professor Gordon Childe in the 1920s and has continued to the present time with the use of modern radiocarbon dating techniques. In 1999 the site was accorded World Heritage Site status by UNESCO as part of the Heart of Neolithic Orkney World Heritage Site.