Alburquerque was conquered from Moors by Ferdinand II of León in 1166. It changed hands couple of times before was finally in the hands of Christians in 1217. The castle was built in the late 13th century.
In the mid-15th century Álvaro de Luna, Master of the Order of St. James, built the famous keep. But that is not the only identifying mark on this castle as it has several palace-style out buildings, some outer defence resources in the barbican and a curious pentagonal tower, crowned battlements with sharp points ending in balls. Furthermore, the fortress is protected by three levels of walls scattered with small towers and several doors.
In the early 18th century the city was in the hands of Portuguese and several Vauban-style bastions were added to the complex.
References:The Broch of Clickimin is a large and well preserved, though somewhat restored broch near Lerwick. Originally built on an island in Clickimin Loch (now increased in size by silting and drainage), it was approached by a stone causeway. The water-level in the loch was reduced in 1874, leaving the broch high and dry. The broch is situated within a walled enclosure and, unusually for brochs, features a large 'blockhouse' between the opening in the enclosure and the broch itself. Another unusual feature is a stone slab featuring sculptured footprints, located in the causeway which approached the site. Situated across the loch is the Clickimin Leisure Centre.