Standing guard above the harbour, this hulking hilltop fortification was begun by the Swedes and finished by the Russians in the late 18th century. Today it contains galleries, craft workshops and fascinating museums, including the history-focused South Karelian Museum, Cavalry Museum and South Karelia Art Museum. Its Orthodox Church, Finland’s oldest church, was completed in 1785 by Russian soldiers. Pick up the tourist office's free walking guide The Fortress of Lappeenranta.