Olavinlinna ("St. Olaf's Castle" or "Olofsborg") is one of the greatest medieval castles in Finland. It was built to secure the eastern border of the Kingdom of Sweden-Finland. The construction started in 1475 by Erik Axelsson Tott. Russians disturbed construction work sequently, because the castle was sited in Savonia to the Russian side of the border established by the Treaty of Nöteborg. Olavinlinna was completed probably in 1483 and there were first a main castle and three towers (Church Tower, Bell Tower and St. Erik's Towers).
Olavinlinna withstood several sieges by the Russians during the First and Second Russian-Swedish wars. Gustav Vasa ordered to erect fourth tower (a "Fat Tower") in 16th century and fifth ("Kilj Tower") was built in the 17th century. The castle was conquered first time by the invading Russians in Great Northern War on 28 July 1714. St. Erik's Tower was badly damaged in cannon fire and Russians demolished it. Olavinlinna was returned to Swedish in Treaty of Uusikaupunki, but they lost it constanly only 23 years later in the end of the Russo-Swedish War of 1741-1743.
Russians enhanced Olavinlinna fortifications and it withstood the siege of Swedish in the war of Gustav III in 1788. The Fat Tower was destroyed in an explosion of gunpowder supply in 1791. When Russians occupied Finland in 1809, Olavinlinna lost its defensive status. It was used as garrison, storage and prison and was abandoded in 1850s. Renovation was started in the end of the 19th century.
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.
Olavinlinna is the initial model for Kropow Castle in the comic book King Ottokar's Sceptre, an album in the series of Adventures of Tintin created by Hergé.
The Château Comtal (Count’s Castle) is a medieval castle within the Cité of Carcassonne, the largest city in Europe with its city walls still intact. The Château Comtal has a strong claim to be called a 'Cathar Castle'. When the Catholic Crusader army arrived in 1209 they first attacked Raymond-Roger Trencavel's castrum at Bèziers and then moved on to his main stronghold at Carcassonne.
The castle with rectangular shape is separated from the city by a deep ditch and defended by two barbicans. There are six towers curtain walls.
The castle was restored in 1853 by the architect Eugène Viollet-le-Duc. It was added to the UNESCO list of World Heritage Sites in 1997.