Suomenlinna (Finnish; until 1918 Viapori), or Sveaborg (Swedish), literal translation in finish is Castle of Finland and in Swedish Castle of Sweden is an inhabited sea fortress built on six islands Kustaanmiekka, Susisaari, Iso-Mustasaari, Pikku-Mustasaari, Länsi-Mustasaari, and Långören and which now forms 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 it as a picturesque picnic site. The Swedish crown commenced the construction of the fortress in 1748 as protection against Russian expansionism. The general responsibility for the fortification work was given to Augustin Ehrensvärd. In the Finnish War the fortress surrendered to Russia on May 3, 1808, paving the way for the occupation of Finland by Russian forces in 1809.