St Catherine's Castle is a Henrician castle in Cornwall, England, built by Thomas Treffry between approximately 1538 and 1540, in response to fears of an invasion of England by France and the Holy Roman Empire. The D-shaped, stone fortification, equipped with five gun-ports for cannon, overlooked the mouth of the River Fowey in Cornwall. It was protected by a curtain wall and the surrounding cliffs.
The castle remained in use for many years until it was closed at the end of the Napoleonic Wars in 1815. Brought back into service in 1855 during the Crimean War, it was fitted with two new artillery positions, but it soon became obsolete and was abandoned. During the Second World War the castle was refortified and used to house a battery of naval guns, protecting the coast against the threat of German attack. At the end of the conflict the castle was restored to its previous condition and is now managed by English Heritage as a tourist attraction.
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.