The Stadttor designed by the architectural firm Petzinka, Overdiek and partners with 20 light-flooded floors and almost 73 metres in height was the official residence of the North Rhine-Westphalian Prime Minister from 1999 to 2017. Glass, steel and beech wood were used for the air-conditioned double façade of the building, which is located close to the harbour in the government district. However, the Stadttor is not a real gate despite the meaning of its name (city gate). Instead, it a 65 metre high building between two “pillars” crossed by floors.