This cover from Sweden depict a joint issue with Finland issued in 2006, celebrating the
Fortress of Suomenlinna. Suomenlinna (Finish), or Sveaborg (Swedish), is an inhabited sea fortress built on eight islands about 4 km southeast of the city center of Helsinki, the capital of Finland. Suomenlinna is popular with tourists and locals who enjoy it as a picturesque picnic site. Originally named Sveaborg (Castle of the Swedes), or Viapori as referred to by Finnish-speaking Finns, it was renamed in Finnish to Suomenlinna (Castle of Finland) in 1918 for patriotic and nationalistic reasons, though it is still known by its original name in Sweden and by Swedish-speaking Finns. 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. The original plan of the bastion fortress was strongly influenced by the ideas of Vauban, the foremost military engineer of the time, and the principles of the star fort style of fortification, albeit adapted to a group of rocky islands. Famous for these bastion fortifications, Suomenlinna became a UNESCO World Heritage Site in 1991.
