The main monument is extraordinary – a cross-shaped setting of stones, centred on a circle of tall stones. At its heart stands a solitary monolith 4.8m high. Lines of smaller stones radiate from the circle to east, west and south. From the north runs an avenue 83m long, formed by two lines of stones that narrow as they approach the circle. Within the circle is a chambered tomb.
Archaeological excavation in the 1980s proved that the main circle was erected 4,500–5,000 years ago, and the chambered tomb a few generations later. Around 3000 BC the climate in the Western Isles was warmer than it is today and the sea-level lower. Salmon ran in the rivers, deer, sheep and cattle grazed the surrounding hills, and barley grew on the broad ridge where Calanais stands. A cult or religion seems then to have swept through the British Isles, involving the building of large earthen enclosures (henge monuments), and impressive circles of timber or stone.
