Cologne lies by the Rhine river, so we need bridges. They are all beautiful and green – chromium oxide green, more precisely, which, in fact, is known as Cologne green. Lord Mayor Konrad Adenauer wanted a patina-like green color and in 1929 Bayer AG mixed the color, which is particularly light and weather resistant.
Image: The particular green of Severin Bridge in Cologne. Copyright: Dietmar Rabich.