Suomenlinna Sea Fortress
historicalA UNESCO World Heritage Site spread across six islands in the Gulf of Finland, Suomenlinna is a historic sea fortress built by Sweden in 1748 to protect against Russian expansion. Accessible by a short ferry ride from Market Square, this living fortress houses museums, tunnels, scenic walking paths, restaurants, and about 800 residents. Visitors can explore the massive stone walls, historic cannons, the Vesikko submarine, and enjoy beautiful Baltic Sea views. The island offers a perfect half-day escape combining history, nature, and stunning coastal scenery.