Alsdorf (German pronunciation:[ˈalsdɔʁf]) is a municipality in the district of Aachen, in North Rhine-Westphalia, Germany. Until the 21st century Alsdorf was a mining area, but now many service companies have established themselves in Alsdorf. Besides, Alsdorf has an indoor arena, a cinema, a mining museum and a zoo. One of Alsdorf's famous sights is the old Castle.