Croisières passant par Mousa Broch, Shetland Islands

A conical dry stone tower dating back to the end of the Iron Age, the Broch of Mousa is one of the many buildings constructed in the Highlands and in the Hebrides, Orkney and Shetlands archipelagos to fend off invaders. Constructed circa 100 BC, it is the tallest broch still standing, at 13 metres (almost 43 feet), and the best-preserved in Europe. Its excellent state of perservation can be explained among other factors by its isolated location and its massive construction: it has a single entrance passage and thick walls, with a diametre that is smaller than that of other brochs. The building was used over the centuries and is mentioned in the Norse sagas, Egil's Saga and the Orkneyinga Saga.