Fodor's Expert Review Bomarsund Fortress
Mariehamn and the Åland Islands
Free
About 8 km (5 miles) from the village of Kastelholm in Sund are the scattered ruins of a huge naval fortress, which was built by the Russians in the early 19th century. It was only half-finished when it was destroyed by Anglo-French forces during the Crimean War. The fortress is open for touring at all times and has explanatory signs. For more information, you'll want to pick up a pamphlet from the small visitor center if it's open.