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.
Hochosterwitz Castle is considered to be one of Austria's most impressive medieval castles. The rock castle is one of the state's landmarks and a major tourist attraction.
The site was first mentioned in an 860 deed issued by King Louis the German of East Francia, donating several of his properties in the former Principality of Carantania to the Archdiocese of Salzburg. In the 11th century Archbishop Gebhard of Salzburg ceded the castle to the Dukes of Carinthia from the noble House of Sponheim in return for their support during the Investiture Controversy. The Sponheim dukes bestowed the fiefdom upon the family of Osterwitz, who held the hereditary office of the cup-bearer in 1209.
In the 15th century, the last Carinthian cup-bearer, Georg of Osterwitz was captured in a Turkish invasion and died in 1476 in prison without leaving descendants. So after four centuries, on 30 May 1478, the possession of the castle reverted to Emperor Frederick III of Habsburg.
Over the next 30 years, the castle was badly damaged by numerous Turkish campaigns. On 5 October 1509, Emperor Maximilian I handed the castle as a pledge to Matthäus Lang von Wellenburg, then Bishop of Gurk. Bishop Lang undertook a substantial renovation project for the damaged castle.
About 1541, German king Ferdinand I of Habsburg bestowed Hochosterwitz upon the Carinthian governor Christof Khevenhüller. In 1571, Baron George Khevenhüller acquired the citadel by purchase. He fortified to deal with the threat of Turkish invasions of the region, building an armory and 14 gates between 1570 and 1586. Such massive fortification is considered unique in citadel construction.
Since the 16th century, no major changes have been made to Hochosterwitz. It has also remained in the possession of the Khevenhüller family as requested by the original builder, George Khevenhüller. A marble plaque dating from 1576 in the castle yard documents this request.
A specific feature is the access way to the castle passing through a total of 14 gates, which are particularly prominent owing to the castle's situation in the landscape. Tourists are allowed to walk the 620-metre long pathway through the gates up to the castle; each gate has a diagram of the defense mechanism used to seal that particular gate. The castle rooms hold a collection of prehistoric artifacts, paintings, weapons, and armor, including one set of armor 2.4 metres tall, once worn by Burghauptmann Schenk.