Although many of the islands' largest mountains, including Ben Nevis, Carrantuohill, Scafell Pike and Snowdon, are Marilyns, many other large peaks such as Cairn Gorm, a number of Munros, and well-known hills such as Bowfell, the Langdale Pikes and Carnedd Dafydd, are not Marilyns because they do not have sufficient height relative to the surrounding terrain (i.e. they have taller "parents"). Not all Marilyns are even hills in the usual sense: Crowborough () sits in a town, whilst Bishop Wilton Wold highest point of the Yorkshire Wolds () lies alongside the A166 road. At the other extreme are Stac Lee () and Stac an Armin (), the two highest sea stacks in the British Isles, in the St Kilda archipelago, west of the Scottish mainland.