Finland also has urbanised regions with many cultural events and activities. The most famous tourist attractions in Helsinki include the Helsinki Cathedral and the Suomenlinna sea fortress. The most well-known Finnish amusement parks include Linnanmäki in Helsinki, Särkänniemi in Tampere, PowerPark in Kauhava, Tykkimäki in Kouvola and Nokkakivi in Laukaa. St. Olaf's Castle (''Olavinlinna'') in Savonlinna hosts the annual Savonlinna Opera Festival, and the medieval milieus of the cities of Turku, Rauma and Porvoo also attract curious spectators.