There have been some fortifications in Lappeenranta city from the 17th century. After the defeat of Sweden-Finland in Great Northern War 1700-1721 Viborg castle and large areas in Carelia were lost to Russia. The military value of Lappeenranta, the new border city, was suddenly increased. The construction of the new bastion fortress was started immediatelly after war in 1721. It was planned to be a part of the new defence system of Finland together with Olavinlinna castle and Hamina fortress.
Russians conquered the fortress in the next war in 1741 after bloody battle. New border was moved to west and Lappeenranta was left to Russian side. Russians settled a garrison to fortress and started to enhance it in the 1750's and again in 1791-1792. After the Finnish War in 1808-1809 fortress lost its military value. After year 1810 it was used as a garrison and prison. During the Finnish Civil War in 1918 red guards were arrested and executed in Lappeenranta fortress.
Nowadays fortress has been renovated and open for visitors. The former garrison buildings are now home to the South Karelian Museum and Art Museum, artists' and craft workshops, Lappeenranta's Orthodox church and parish hall, a children's art school and a café, among others.
Saint-Georges de Boscherville Abbey is a former Benedictine abbey. It was founded in about 1113 by Guillaume de Tancarville on the site of an earlier establishment of secular canons and settled by monks from the Abbey of Saint-Evroul. The abbey church made of Caumont stone was erected from 1113 to 1140. The Norman builders aimed to have very well-lit naves and they did this by means of tall, large windows, initially made possible by a wooden ceiling, which prevented uplift, although this was replaced by a Gothic vault in the 13th century. The chapter room was built after the abbey church and dates from the last quarter of the 12th century.
The arrival of the Maurist monks in 1659, after the disasters of the Wars of Religion, helped to get the abbey back on a firmer spiritual, architectural and economic footing. They erected a large monastic building one wing of which fitted tightly around the chapter house (which was otherwise left as it was).