A series of stone alignments and a stone circle on the southern part of the Isle of Lewis in the Outer Hebrides of western Scotland. This complicated site was partly covered in up to 1.5 m of peat until the late 19th century ad. Investigations by Gerald and Margaret Ponting and excavations by Patrick Ashmore in 1980 and 1981 have revealed a great deal about the history of the site. Perhaps most surprising is that prior to the construction of the stone monuments the area had been farmed. In the early 3rd millennium bc a stone circle comprising thirteen pillars of local gneiss was built with a single large pillar in the centre. The circle is approached from the north by a stone avenue, while single stone rows lead away to the west, south, and east. Some time after the circle and the alignments were built a small passage grave was constructed between the pillars of the circle and the central standing stone on the east side. It has been suggested that Callanish incorporated a series of lunar alignments looking down the stone avenue through the circle onto the southern horizon when, every 18.6 years, the moon dances low over the hills to the south, sets, and then gleams brightly, throwing the stones of the stone circle into silhouette as it passes a notch in the horizon.
P. Ashmore, 1995, Calanais: the standing stones. Stornoway: Urras nan Tursachan