A decade after Swiss architect Peter Zumthor won a competition to design a new home for the Kolumba Art Museum, in Cologne, his building is finally set to open September 15. Best known for his Thermal Baths in Vals, Switzerland, Zumthor here puts his minimalist imprimatur on a monolithic gray-brick facade with only patches of decorative perforations and oversized windows to let in daylight. The museum envelops the Madonna in Ruins chapel, designed by Gottfried Bohm in 1949, and sits atop the remains of the 1853 St. Kolumba church, destroyed in World War II. Zumthor’s voluminous structure will better accommodate the collection—ranging from Leonhard Kern’s 1630 frieze of Adam and Eve to Josef Albers’s 1962 Homage to the Square.—Diana Lind