Suomenlinna (Finnish, until 1918 Viapori), or Sveaborg (Swedish), literal translation in Finnish is Finland Castle and in Swedish Sweden Castle is an inhabited sea fortress built on six islands Kustaanmiekka, Susisaari, Iso-Mustasaari, Pikku- Mustasaari, Länsi-Mustasaari and Långören and which is now part of the city of Helsinki, the capital of Finland. Suomenlinna is a UNESCO World Heritage Site and popular with tourists and locals, who enjoy picnicking. The Swedish crown began construction of the fortress in 1748 as a protection against Russian expansionism. Overall responsibility for the fortification work was entrusted to Augustin Ehrensvärd. In the Finnish War the fortress surrendered to Russia on 3 May 1808, paving the way for the occupation of Finland by Russian forces in 1809.