The imposing main walls and their four towers of Yverdon-les-Bains castle follow the geometric characteristics used for lowland castles. It was planned out between 1260-1270 by the young mason and architect James of St. George. He would later travel to England where he would become the master castle builder for King Edward I. James would be responsible for building a series of castles (known as the 'Iron Ring') in North Wales following its conquest by the English Crown.
Yverdon's castle used to be the residence of the castellans of the Savoy dynasty, until 1536, followed by the bailiffs of Bern state. In 1798, the Département du Léman became the castle's owner. The Département had been set up by the short-lived Helvetic Republic (1798–1803), imposed by Napoleon I.
A few years later, Yverdon acquired the castle, to entrust it to Johann Heinrich Pestalozzi and his institute. After 1838, the castle housed a public school. New classrooms were created, especially on the second floor: dividing walls were erected, additional windows changed the severe look of the castle's façade. After 1950, these classrooms were gradually abandoned; the last classes left in 1974. The original medieval structure was then restored. The castle is today a multi-purpose cultural centre, housing a regional museum, a theatre, various conference rooms and the oldest public library of French-speaking Switzerland, founded already in 1763. The library is now part of the castle museum, existing since 1830.References:
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.