The office tower Stadttor in the Unterbilk part of Düsseldorf in the state of North Rhine-Westphalia. It was designed by the architects Petzinka, Overdiek and Partner and is home and seat of the prime minister of North Rhine-Westphalia. It is located in the government district of the city and was opened in 1998. The distinct red building next to it is the Portobello tower, another office building built by the architects Döring, Dahmen, Joeressen