Created for the south transept of the Cologne Cathedral, Gerhard Richter's stained glass window is a must-see work for visitors to Cologne. The original window was destroyed during World War II and had been replaced with plain glass. Inspired by Richter's 1974 painting 4096 Farben, the window consists of 11,500 hand-blown glass squares in 72 different colours. Echoing the colours of surrounding windows, Richter's illuminated abstraction blends a modernist aesthetic with the Gothic ecclesiastical architecture of the cathedral.