The Rheinturm (pronounced) (Rhine Tower) is a 240.5 metre high concrete telecommunications tower in Düsseldorf, capital of the federal state (Bundesland) of North Rhine-Westphalia, Germany. Construction commenced in 1979 and finished in 1981. The Rheinturm carries aerials for directional radio, FM and TV transmitters. It stands 174.5 metres high and houses a revolving restaurant and an observation deck at a height of 170 metres. It is the tallest building in Düsseldorf. The Rheinturm was inaugurated on 1 December 1981. It contains 7,500 cubic metres of concrete and weighs 22,500 tons. Before October 15, 2004, when an aerial antenna for DVB-T was mounted, it was 234.2 metres high. The observation deck is open to public, daily from 10:00 AM to 11:30 PM. As a special attraction, a light sculpture on its shaft works as a clock. This sculpture was designed by Horst H. Baumann and is called Lichtzeitpegel (light time level). The light sculpture on the Rheinturm is the largest digital clock in the world.