the north-west and south-east. The ditch appears to have been created in sections, possibly by workforces from different parts of Orkney. The stones may have been a later addition, maybe erected over a long period of time. Examination of the immediate environs reveals a concentration of ancient sites, making a significant ritual landscape. Within there are the two circle-henges, four chambered tombs, groups of standing stones, single stones, barrows, cairns, and mounds. The immediate area has also yielded a number of flint arrowheads and broken stone mace-heads that seem to date from the Bronze Age. Although its exact purpose is not known, the proximity of the Standing Stones of Stenness and its Maeshowe tomb make the Ring of Brodgar a site of major importance. The site is a scheduled monument and has been recognized as part of the "Heart of Neolithic Orkney" World Heritage Site in 1999. World Heritage status The Heart of Neolithic Orkney was inscribed as a World Heritage site in December 1999. In addition to the Ring of Brodgar, the site includes Maeshowe, Skara Brae, the Standing Stones of Stenness and other nearby sites. It is managed by Historic Environment Scotland, whose 'Statement of Significance' for the site begins: The monuments at the heart of Neolithic Orkney and Skara Brae proclaim the triumphs of the human spirit in early ages and isolated places. They were approximately contemporary with the mastabas of the archaic period of Egypt (first and second dynasties), the brick temples of Sumeria, and the first cities of the Harappa culture in India, and a century or two earlier than the Golden Age of China. Unusually fine for their early date, and with a remarkably rich survival of evidence, these sites stand as a visible symbol of the achievements of early peoples away from the traditional centres of civilisation...The Ring of Brodgar is the finest known truly circular late Neolithic or early Bronze Age stone ring and a later expression of the spirit which gave rise to Maeshowe, Stenness and Skara Brae The first formal survey of the Ring of Brodgar and surrounding antiquities was performed in 1849 by Royal Navy Captain F.W.L. Thomas of HM cutter Woodlark. Captain Thomas was in the area drawing up Admiralty Charts in 1848–49, and he and his crew performed archaeological surveys as well resulting in the publication in 1852 of The Celtic Antiquities of Orkney. Excavations of Neolithic