The most famous resident at Copenhagen's Rådhus (City Hall) is the curious Jens Olsen's World Clock, designed by astromechanic Jens Olsen (1872–1945) and built at a cost of one million kroner. Not only does it display local time, but also solar time, sidereal time, sunrises and sunsets, firmament and celestial pole migration, planet revolutions, the Gregorian calendar and even changing holidays!