Boreray rises abruptly from the sea to 384 metres, six kilometres northeast of Hirta. Beside it stand Stac an Armin (196 m) and Stac Lee (172 m), the two highest sea stacks in Britain. Together they hold one of the largest colonies of northern gannets in the world — tens of thousands of pairs — and the cliffs and sea around them are white and loud with birds.
You can't land, but most day trips circle Boreray and the stacs on the way home, and it's often the most memorable part of the day. The St Kildans did land, climbing the stacks to harvest birds and eggs and keeping a distinctive breed of horned Boreray sheep on the island.