Fortress Hohensalzburg is the largest preserved Medieval fortress in Central Europe, originally founded by Salzburg's Archbishop Gebhard, who was a great supporter of the pope in the controversy against the Holy Roman Emperor.
Over the centuries, the castle has grown and grown mostly founded by the Archbishops who were using it ocassionally as a residence, then as a fortress against invaders and their own rebellious subjects.
The outside does look grim, although inside there are lavish state rooms, such as the glittering Golden Room, the Burgmuseum -- a collection of medieval art --and the Rainer's Museum, showing off its brutish arms and armor.