Cologne sewerage system

The Romans laid the first sewers under the city, and the arrangement changed little for roughly 1,800 years. As the population climbed through the 19th century, the old system could no longer cope, and untreated sewage was channelled into the Rhine, bringing disease and odour. In 1828 the English poet Samuel Taylor Coleridge described the city as having „two and seventy stenches, all well defined, and several stinks!“ While Paris and London modernised their sewers in the 1850s, Cologne's present network came later, under the architects Johann Stübben and Carl Steuernagel. By 1900 the boroughs of Deutz, Nippes and Ehrenfeld were connected. A mechanised waste-water plant followed in 1905, and five purification plants now filter the water before it is released into the Rhine.

The Kronleuchtersaal takes its name from chandeliers fitted into the ceiling to impress Emperor Wilhelm II, who in the end did not attend the opening ceremony. A single electric chandelier was added in 1990. The room has hosted jazz and classical concerts for audiences of up to 50 people. A stone plaque records the names of the architects and Wilhelm von Becker, the mayor at the time. The area is listed as protected.