RWE Tower, Office skyscraper in Südviertel, Essen, Germany.

The Evonik Tower is a 127-metre office high-rise in Essen with 26 office floors above ground, two technical floors between the 17th and 18th, and a 51-sided polygonal plan 32 metres across. Christoph Ingenhoven designed it; the double-glazed facade allows natural ventilation and the antenna reaches 162 metres.

The building was completed in late 1996 as Essen transformed from an industrial city into a modern business center. Its construction marked a shift in the region when outdated factories made way for contemporary office spaces.

The tower's walls and park hold commissioned art: Lothar Baumgarten placed word creations from business, politics and culture in the staff casino and ground floor, Norbert Thomas made the stainless-steel sculpture Springende Linie in the park behind the tower, and Richard Long laid the stone work Neandertal Line there. François Morellet created a sculpture for each floor, varying in form from storey to storey.

The tower sits in central Essen and is easily accessible by public transportation. While you can walk around the building and see it from nearby streets, interior access is limited to company employees and scheduled visitors.

The tower's footprint is a 51-sided polygon 32 metres across, and one of its nine lifts runs outside the building. In the park behind it stand Norbert Thomas's stainless-steel sculpture Springende Linie and Richard Long's stone work Neandertal Line, set against the glass facade.