The Clock Tower (Zytglogge) was the first western gate of the city (1191 - 1256) and, with its famous astronomical calendar clock built in 1530, is now one of the main attractions of Bern and the oldest clocks in Switzerland.The tower clock served as the master clock for the city of Bern and hence set the standard. From there, the hours were measured which are indicated on the hour stones of the canton’s roads.The hour chimes, the two tower clocks, the mechanical figures and the astronomical clock are all driven by a common mechanism.The exterior appearance of the tower is dominated by late-Baroque elements. The large dial is framed by a fresco produced by Viktor Surbek in 1930.