Suomenlinnalinnoitus

Suomenlinnalinnoitus, commonly known as Suomenlinna, is a sea fortress located on a group of islands near Helsinki, Finland. It was built in the 18th century by Sweden to defend Helsinki and the Baltic approaches, and it represents an important example of early modern military architecture in the region.

Construction began in 1748 under the supervision of Augustin Ehrensvärd. The fortress comprises walls, bastions, batteries, barracks, cisterns and a network of tunnels and fortifications spread across several islands, connected by landbridges and sea walls. The project continued through the later 18th century as new defensive needs arose and the site expanded.

Following the Finnish War of 1808–1809, control of the fortress passed to the Russian Empire and it was renamed Sveaborg. It remained a major coastal fortress in Russian hands for much of the 19th century. After Finland’s independence in 1917, the site came under Finnish control and gradually transitioned from a military installation to a cultural and historical monument.

In 1991, Suomenlinna was inscribed on the UNESCO World Heritage List for its value as a well-preserved example of 18th-century fortification and naval defense architecture, illustrating the historical ties between Sweden, Russia and Finland. Today the fortress is a major tourist and cultural site, with museums, guided tours and events. It is accessible by ferry from Helsinki’s Market Square, and its preserved fortifications continue to be part of Helsinki’s urban landscape and national heritage.