Prague Orloj is not the only one astronomical clock in the Czech Republic but it certainly is the oldest and the best known.
Olomouc, the former capital of Moravia in the eastern part of the Czech Republic, also has an impressive exterior astronomical clock on the main town square.
Dating originally from 1420, the clock was remodelled approximately once every century. When the retreating Nazi German army passed through Olomouc in the final days of the war in May 1945 they opened fire on the old astronomical clock, leaving only a few pieces (that can now be seen in the local museum). As a result of the serious damage the clock was reconstructed in the style of socialist-realism in the first years of communist rule in Czechoslovakia (late 1940s-early 1950s). The religious and royal figures were replaced with athletes, workers, farmers, scientists and other members of the proletariat, while the glockenspiel was altered to play three pieces of traditional local music.
The lower dial represents the earthly sphere and indicates minute, hour, day, month, year and phase of the moon. The upper dial represents the heavenly sphere and shows a star map, the sun, earth and planets against a background of the twelve houses of the zodiac. The third and highest level is where the saints and apostles once paraded during the daily musical display (at 12 noon). Their role is now performed by faded-looking volleyball players, auto mechanics and factory workers.
The intricate background mosaic covers the clock's entire height of 14 metres and has representations of the twelve seasons and two traditional festival; the ride of the kings and the procession of maidens.