Dùn

Its name simply means "fort" in Scottish Gaelic (for more information, see "dun"), but the fort itself has been lost – old maps show it on Gob an Dùin (NF109972), which is at the seaward end.

This prevents Soay sheep from Hirta straying onto the island, and thus it is more vegetated.

The small island is home to the largest colony of fulmars in Britain.

Before 1828, St Kilda was their only British Isles breeding ground, but they have since spread and established colonies elsewhere, such as at Fowlsheugh.

MacLean (1972) suggests that the arch was broken when struck by a galleon fleeing the defeat of the Armada, but other sources, such as Mitchell (1992), provide the more credible (if less romantic) explanation that the arch was simply swept away by one of the many fierce storms which batter the islands every winter.