Ruotsinsalmi fortress was built by Russians in 1790-1796. It was part of the South-Eastern Finland fortification system which was planned to defence St. Petersburg. The sea fortress was located to islands in front of the city of Kotka and Kyminlinna fortress. It contained three main strongholds (Fort Katarina, Fort Elisabeth and Fort Slava) and several redoubts and artillery batteries.
Ruotsinsalmi fortress lost its original defensive value only couple of years later, when rest areas of Finland were joined to Russia after the Finnish War (1808-1809). It was disbanded in the 1830's and during the Crimean war (1855) Anglo-French fleet destroyed the empty fortress permanently.
Today individual remnants of fortresses can still be found for instance beside Catherine’s path and on the island of Tiutinen. Also Fort Elisabeth's embankments have been renovated in recent years. The island is easily accessible by regular boat services in the summer.
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.