The Outer Hebrides, also known as the Western Isles, is an island chain off the west coast of mainland Scotland. There are 15 inhabited islands and there are more than 50 substantial uninhabited islands in the Outer Hebrides. This is a long island chain, from Barra Head in the south to the Butt of Lewis in the north is roughly 130 miles. The main islands form an archipelago of which the major islands include Lewis and Harris, North Uist, Benbecula, South Uist, and Barra. In fact, Lewis and Harris is the largest island in Scotland and the third largest in the British Isles, after Great Britain and Ireland! There are also more than 7,500 freshwater lochs in the Outer Hebrides, about a quarter of the total for the whole of Scotland. The islands feature a wealth of historical sites including the Callanish Stones dating from about 2900 BC which is the finest example of a stone circle in Scotland, the 13 primary monoliths of between one and five metres high, Cladh Hallan on South Uist, which is the only site in the UK where prehistoric mummies have been found and the impressive ruins of Dun Carloway broch on Lewis both date from the Iron Age.