Broch of Mousa (or Mousa Broch) is a preserved Iron Age broch or round tower. It is on the island of Mousa in Shetland, Scotland. It is the tallest broch still standing and amongst the best-preserved prehistoric buildings in Europe. It is thought to have been constructed c. 100 BC, and is one of more than 500 brochs built in Scotland. The site is managed by Historic Environment Scotland as a scheduled monument. Location The broch is located on the western shore of the island of Mousa (). It is accessible by boat from Sandwick, Shetland, south of Lerwick. It stands on the flat rock surface of a low promontory near the shore overlooking Mousa Sound. It is the tallest broch still standing and amongst the best-preserved prehistoric buildings in Europe. Description Mousa Broch has one of the smallest overall diameters of any broch, as well as one of the thickest wall bases and smallest interiors; this massive construction (as well as its remote location) is likely to be the main explanation for its excellent state of preservation. It stands high and is accessible via a single entrance at ground level. Once inside, a visitor may ascend an internal staircase to the top. It is the only broch which is complete nearly to the top, including the original intramural stair. It is built of dry stone with no mortar. The entrance is on the west side but has been altered at various times from its original appearance. The entrance passage is long and still has an original bar-hole. Inside a hearth and floor tank can be seen in the central space. There is a low stone bench around the base of the inside wall, which was part of an early alteration to the interior. The broch went through at least two phases of occupation. In its original condition it may or may not have contained a wooden roundhouse resting on the scarcement ledges and presumably on a ring of posts set into the primary floor. (It has recently been argued that the scarcements may have supported scaffolding in a roofless building. At a later date, if the wooden building existed, it was demolished to make way for a small wheelhouse (with three projecting stone piers) in the interior. Scarcement ledges at heights of might have supported the putative timber building. The other main feature of the ground floor is the