monolith

Single isolated stone or column, usually standing and of great size, used as a form of monument. Some are natural features, such as the Buck Stone in the Forest of Dean, England. Other monoliths may be quarried, resited, finished, or carved; those in Egypt of about 3000 BC take the form of obelisks. They have a wide distribution including Europe, South America, North Africa, and the Middle East.

Apart from their ritual or memorial function, monoliths have been used as sundials and calendars in the civilizations of the Aztecs, Egyptians, and Chaldeans (ancient peoples of southern Babylonia). In landscape archaeology, monoliths are interpreted in a wider context, possibly as boundary markers. The largest cut stone, weighing about 1,500 tonnes, is sited in the ancient Syrian city of Baalbek.