Hochtief AG is a German construction company based in Essen, North Rhine-Westphalia, Germany. Hochtief is Germany's largest construction company and operates globally, ranking as one of the largest general construction companies in the United States through its Turner subsidiary, and in Australia through a 90% shareholding in CIMIC Group. In 2010 it employed more than 70,000 employees across five corporate divisions. One of these, Hochtief Concessions, is a major airport operator. The others are involved with construction project planning, finance, construction and operation. Work done in 2010 was €23.23 billion, with more than 80% coming from operations outside Germany.

Essen is the central and, after Dortmund, second-largest city of the Ruhr, the largest urban area in Germany. Its population of 584,580 makes it the fourth-largest city of North Rhine-Westphalia after Cologne, Düsseldorf and Dortmund, as well as the ninth-largest city of Germany. Essen lies in the larger Rhine-Ruhr metropolitan region, second largest by GDP in the EU, and is part of the cultural area of Rhineland. Because of its central location in the Ruhr, Essen is often regarded as the Ruhr's "secret capital". Two rivers flow through the city: the Emscher in the north, and in the south the Ruhr River, which is dammed in Essen to form the Lake Baldeney (Baldeneysee) and Lake Kettwig reservoirs. The central and northern boroughs of Essen historically belong to the Low German (Westphalian) language area, and the south of the city to the Low Franconian Bergish area.