... is on the hill overlooking the Danube and is the town's most prominent landmark. In the 9th century it was a Great Moravian fortress. In the 10th century, it was rebuilt to become the King's residence and a border post. It has been rebuilt every century since and according to almost every possible style. The floorplan it has today dates back to the reign of Sigmund of Luxemburg (during the first half of the 15th century). There were later Renaissance and Baroque additions. During the reign of Maria Theresia, it became an imperial palace. After a fire in 1811, the castle began to go to ruins. Reconstruction began in 1954 and it went unused until 1968. On the east side, remains of a 9th century Great Moravian Basilica were found.