Olavinlinna, a 15th century three-tower castle located in Savonlinna, Finland
Savonlinna (The Finnish name means Castle of Savonia.) is a town and a municipality of 27,828 (28 February 2009) inhabitants in the southeast of Finland, in the heart of the Saimaa lake region.
The city was founded in 1639, based around Olavinlinna. The castle was founded by Erik Axelsson Tott in 1475 in an effort to protect Savonia and to control the unstable border between the Kingdom of Sweden and its Russian adversary. During the Russo-Swedish War (1741–1743), the castle was captured by Field-Marshal Peter Lacy. It was held by Russia between 1743 and 1812, when it was granted back to Finland as a part of the "Old Finland".
Olavinlinna (Swedish: Olofsborg; literally St. Olaf's Castle) is a 15th century three-tower castle located in Savonlinna, Finland. It is the world's most northern medieval stone fortress still standing.
Currently, the castle hosts several small exhibitions, including the Castle Museum which displays artifacts found in the castle or related to it, and the Orthodox Museum which displays icons and other religious artifacts both from Finland and Russia. The castle forms a spectacular stage for the Savonlinna Opera Festival, held annually in the summer since 1912.
References sources : wikipedia, 芬兰旅游局