Holding some of Finland’s most important military history, Suomenlinna Sea Fortress is a UNESCO World Heritage Site and one of Helsinki’s top tourist attractions. Spread over six islands in the Gulf of Finland, Suomenlinna is easy to reach by ferry from Helsinki. It is easily reachable by JT-Line ferry during summertime and by HSL ferry from the Market Square all year round. Just hop on a ferry and in about 20 minutes you will admire Suomenlinna - the priceless treasure of Finland and the biggest sea fortress in the world. Historically evocative and visually striking, it boasts beautiful nature, stunning coastal views, fortress walls, museums, picnic spots, cafés and the country’s only remaining World War II submarine. Just do not forget to take the perfect selfie here!