
Kärnäkoski Fortress is a bastion fort constructed between 1791 and 1793 on the Saimaa isthmus near Savitaipale, built as part of Russia's protective fortress chain against Swedish incursions. Organized by the renowned Russian General Aleksander Suvorov, the fortress was constructed entirely from boulders collected from the surrounding countryside without any excavation, with stones gathered from the local terrain. Located on the shores of Lake Saimaa adjacent to rapids connecting Saimaa to Lake Kuolimo, the fortress features landscape integrated with the traditional lakeland environment. Though it never engaged in direct military action, several Civil War battles occurred nearby in 1918. Now listed as a nationally significant cultural historic landmark by Finland's National Board of Antiquities and Ministry of the Environment, the restored fortress is accessible to visitors with directional signage, though guided tours and formal tourist services are not currently available.