The Kolumba Museum is located in Cologne, Germany, which is a city almost completely destroyed by World War II. The site of the Museum used to be a late-gothic church in which he respected when making the museum by preserving its essence, and is described to make you feel its spiritual values in it.
On the inside of the building, the walls are grey bricks that are articulated with perforations so that light is diffused and only fills up specific spaces of the rooms.
Zumthor is known for taking his time when designing projects until he finds the perfect materials, and with this building he had special bricks made by Petersen Tegl of Denmark, and he fired the bricks with charcoal to put of the perfect shade of color for the building.
http://www.archdaily.com/72192/kolumba-musuem-peter-zumthor