Suomenlinnan

Suomenlinnan, commonly known as Suomenlinna, is a sea fortress on a group of islands off Helsinki, Finland. It is known in Finnish as Suomenlinna and in Swedish as Sveaborg. Construction began in 1748 under Swedish rule to defend the approaches to Helsinki from Russian expansion. The fortifications were designed and led by the military engineer Augustin Ehrensvärd and were expanded through the 1770s. The fortress comprises a network of bastions, walls, magazines, and batteries on several islands near the city.

During the Finnish War of 1808–1809, Russian forces captured Sveaborg after a lengthy siege; it remained under Russian control until Finland's independence in 1917, when the fortress was renamed Suomenlinna. In 1991, UNESCO inscribed the Sea Fortress of Suomenlinna as a World Heritage Site.

Today, the area is both a cultural site and a residential district. It houses museums such as the Ehrensvärd Museum and the Suomenlinna Museum, the Suomenlinna Church, and preserved 18th-century fortifications that illustrate maritime defense architecture. The islands are connected by ferries from Helsinki's Market Square, and the site is a popular destination for visitors and locals alike.