barrow, in archaeology, a burial mound. Earth and stone or timber are the usual construction materials; in parts of SE Asia stone and brick have entirely replaced earth. A barrow built primarily of stone is often called a cairn. Barrows occur in many parts of the world; they were built during the Neolithic period in Western Europe and in recent times in Buddhist countries. In European prehistory the characteristic barrows are either long or round. The long ones are from the Neolithic period and often contain several burial chambers. They may have been intended to simulate cave burials. The stone chambers were placed at one end of the mound and were approached by a passage, sometimes over 300 ft (90 m) in length. Round barrows, usually dating from the Bronze Age, normally contain a single burial. The round barrow was commonly bell shaped; another type had a low central mound that invariably contained cremated remains and was surrounded by a walled ditch or a circle of standing stones, usually about 150 ft (50 m) in diameter. Barrow building in Europe continued until the Christian era. Roman, Saxon, and Viking barrows are known, though such burials were apparently reserved for important personages. The erection of mounds over burials has been widespread (see tomb). The round barrow or stupa of Asia is usually a shrine for relics of the Buddha. See megalithic monuments and Mound Builders.