Suomenlinna (Swedish: Sveaborg) is a sea fortress located off Helsinki and a district of about 700 inhabitants. As a historical monument and attraction, its cultural value is significant, and it is a strong part of Helsinki's identity. The construction of Suomenlinna started in 1748, and until 1918 it was known in Finnish as Viapor, based on its Swedish name Sveaborg. Suomenlinna was added to the UNESCO World Heritage List in 1991. Suomenlinna is one of the most popular tourist destinations in Finland. In 2019, the fortress was visited by around one million visitors. Various neighborhood and cultural events are organized in Suomenlinna throughout the year. There are many cafes and restaurants located on the islands. Suomenlinna is renovated and maintained by the Suomenlinna Management Board, which is a state agency under the Ministry of Education and Culture. Nowadays, the only military institution on the islands is the Naval Academy located in Pikku Mustasaari. Suomenlinna prison, established in 1971, is located at the southern tip of Iso Mustasaari, under the authority of the Criminal Sanctions Department. A key part of the repair work on walls, ramparts and buildings is done as prisoner work. The prison has places for about 100 prisoners.[1] In the northwestern part of Iso Mustasaari, there is an archive and museum cave used by the nursing board.[2]