Suomenlinna Linnoitus (Fortress)

Construction of the Suomenlinna Fortress began in 1748 under Swedish rule. The reason was Russia's growing military presence in the Baltic Sea after the founding of St. Petersburg. Under the direction of Augustin Ehrensvärd, a strategically important defensive complex was built. In the Russo-Swedish War of 1808–1809, the then commander Carl Olof Cronstedt capitulated and handed over the fortress to Russian troops, marking the end of 600 years of Swedish rule over Finland. Under Russian control, the complex was further expanded and shelled by Allied forces during the Crimean War (1854–1856), causing significant damage. After Finnish independence in 1918, the fortress, named Suomenlinna (Finland's Castle), became part of the Finnish state and gradually lost its military importance before being transferred to the Ministry of Education for administration in 1974.

The Suomenlinna Fortress is located on islands off the port of Helsinki in the Helsinki district, Uusimaa region, Finland, at an elevation of approximately 5 m above sea level.

The Suomenlinna Fortress is now accessible to visitors and can be explored. It houses museums and is home and workplace to around 1250 people.

• Raaseporin linna (Castle) (Ruins), approx. 76.1 km away
• Svartholman Merilinnoitus (Fortress) (Fortress), approx. 77.4 km away
• Hämeen linna (Castle) (Castle), approx. 100.0 km away
• Haminan Linnoitus (Fortress) (Fortress), approx. 131.1 km away