Introduction to Thun Castle: Thun Castle is located on a high hill overlooking Lake Thun. It is said to have been built by the Duke of Chailingen who built Bern at the end of the 12th century. The main building is a square tower with a corner tower at each corner. Today, the main tower of the castle is used as a history museum (built in 1888). The exhibits include ancient weapons, ancient tapestries, and the evolution of Swiss military uniforms and weapons through the ages.