All the islands of the St Kilda group rise abruptly from the ocean floor at a depth of about 70m. The two major rock formations, the granite and the gabbro have eroded to give quite different topography. The granite hills, Conachair and Oiseval, are smooth paps; the gabbro hills, Dun, Mullach Bi, the Cambir, Soay, Boreray and the major stacks, are castellated, bastion-like masses. On Hirta, the flowing contours of Mullach Sgar, Mullach Mor, Conachair and Oiseval, together with the horseshoe of Village Bay, combine to form a steep amphitheatre open to the sea on the south-east. Gleann Mor possesses the same smooth outline and wide, U-shaped form, but opens to the north. The highest point on Hirta is the beautiful cone of Conachair. Mullach Sgar is connected to the hogback ridge of Mullach Geal and Mullach Mor by Am Blad, a broad col over 320m high between these north and south bays. The views in either direction, but particularly over Village Bay, are stunning and emphasise the vertical scale of the islands. Mullach Bi on the rugged west coast is the second highest summit; it is joined by a narrow neck to the Cambir, the most northerly point of Hirta. The Amhuinn Mhor and the Amhuinn a'Ghlinne Mhoir are the only streams of any size. Freshwater springs occur at several localities on Hirta, with other springs on Soay and Boreray, but not on Dun. A cruise below their towering walls amongst the screaming seabirds, is an unforgettable, humbling and awe-inspiring experience even without ever landing on these satellite islands.

Sea cliffsThe official description of the St Kilda National Scenic Area is disappointingly brief, highlighting that one must visit the place to fully appreciate its sheer scale and stark beauty. ‘The description of St Kilda that does not contain superlatives has not been written … the islands are of volcanic origin and have been weathered by the ocean into profiles that never fail to impress all who set eyes upon them. The three larger islands … exhibit precipices that plunge into the sea. Stark, black, precipitous cliffs contrast with steep grassy green slopes and every element seems vertical. Caves and stacks are a feature of every coast except the smooth amphitheatre of Village Bay on Hirta, and the cliffs are thronged with sea-birds, gannet and fulmar being more prolific here than anywhere else in Britain.’ Sir Julian Huxley called Stac Lee ‘... the most majestic sea rock in existence’ and Geikie has described Conachair as follows: ‘Nowhere among the Inner Hebrides, not even on the south-western side of Rum, is there any such display of the capacity of the youngest granite to assume the most rugged and picturesque forms. It is hardly possible to exaggerate the variety of outline assumed by the rock. To one who boats underneath these cliffs the scene of ceaseless destruction which they present is vividly impressive. Boreray and Soay are no less impressive with their cliff-girt green turf pasture, and Dun has a highly crenellated profile.’ This curt paragraph hardly does justice to St Kilda but the photographs and images included in this World Heritage submission will speak more eloquently to those who have yet to experience the islands in person.