The St Kilda volcanic archipelago has the highest sea cliffs in Britain and the most important seabird breeding colonies in northwestern Europe. The entire archipelago is owned by the National Trust for Scotland and is one of the few UNESCO World Heritage Sites chosen for both its natural and cultural qualities. In spite of its extreme isolation, some 40 miles (64 km) off of the remote Hebrides, there has been permanent habitation here for 2,000 years. The one-time population of hardy Kildians were finally forced to leave because of starvation. Their abandoned stone huts stand as silent witnesses to past settlement, but two of their ancient sheep species, dating from the Neolithic and Iron Ages, continue to thrive here.
Some one million nesting seabirds breed in St Kilda, including the largest colony of guillemots on earth, and the largest colony of gannets, fulmars, Leach's petrels and Atlantic puffins in Britain. The St Kilda wren and the St Kilda field mouse are species found only here.