Alloa Tower is an early 14th century tower house that served as the medieval residence of the Erskine family, later Earls of Mar. Retaining its original timber roof and battlements, the tower is one of the earliest, and largest, of Scottish tower houses, with immensely thick walls.
It was originally built as part of a line of fortifications defending the north shore of the Firth of Forth. Several 19th century works, including Groome's Gazetteer, date the tower to the year 1223. Archaeological investigations from the early 1990s date the original fortified house to the early 14th century, where it had a cellar that sometimes served as a pit prison. By the mid-14th century it had been enlarged with a great hall and rose to three storeys in height, with the entrance on the first floor. In the 15th century it was further enlarged to four/five levels while retaining its first-floor access. Late in the 16th century ground-floor access was probably added.
John Erskine, 6th Earl of Mar built a very large mansion (Alloa House) in 1710 that incorporated the tower as its annexe; he made plans to remodel the tower's interior, but it is unclear what changes were actually made. The house burned down in 1800 and was rebuilt by George Angus in 1834–1838 for the 9th Earl. It was demolished sometime after 1868.
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.