The famous carillon tower is perched on top of the Neue Residenz (New Residence), Prince-Archbishop Wolf-Dietrich's government palace. The carillon is a later addition, brought from today's Belgium in 1695 and finally put in working order in 1704. The 35 bells play classical tunes (usually by Mozart or Haydn) at 7 am, 11 am, and 6 pm—with charm and ingenuity. From Easter to October, the bells are immediately followed by a resounding retort from perhaps the oldest mechanical musical instrument in the world, the 200-pipe "Bull" organ housed in the Hohensalzburg Fortress across town. Details about the music selections are listed on a notice board across the square on the corner of the Residenz building.