Today Orkney retains a vast archaeological treasury of buildings, artefacts and evidence from this time. In recognition of this, "The Heart of Neolithic Orkney" was inscribed on the World Heritage List by UNESCO in 1999. Because of their outstanding universal value, "The monuments of Orkney, dating back to 3000-2000BC, are outstanding testimony to the cultural achievements of the Neolithic peoples of northern Europe." This guide covers all of the monuments in the nominated area, as well as many contemporary places of interest throughout Orkney. The village of Skara Brae, stone circles of the Ring of Brodgar and the Standing Stones of Stenness, and Maeshowe Chambered Cairn are described in depth. Isolated standing stones, such as the Watchstone, chambered cairns, such as Unstan and more enigmatic sites all over Orkney are included. The major current excavations at the Ness of Brodgar and Links o' Noltland on Westray show that much remains to be discovered about Neolithic Orkney. Numerous smaller scale digs in various other places have elucidated the study of Neolithic houses. Small settlements and isolated homesteads were widespread across Orkney during the Neolithic, reaching a peak c.3000BC, before sharply falling until c.2800BC. There was a revival which peaked c.2500BC, followed by abandonment c.250 years later.