Built in 1369, the massive bulk of Threave Castle is a major landmark in the Stewartry countryside. Once the home of the ‘Black Douglases’ it stands 21 meters high and has 5 storeys. Built on an island, it was once accessed by a movable bridge from the gatehouse to the first floor. This level is vaulted, and was occupied by kitchens. Below is a basement with a well and prison pit. A spiral stair within the 2m thick wall leads up to the great hall, which had a second bridge access to the upper gatehouse. Above this were two timber floors, now missing, with two rooms on the next storey, and servants quarters at the top. Holes in the external walls would have supported a timber defensive structure known as a bretache, which allowed the defenders to drop objects on attackers at the walls. The Historic Scotland website has full details.