There is something incredible about the buildings in Cologne as they relate to material and mass. Of course, this has much to do with the fact that many of Gottfried Bohm's bulidings are in the area, as well as the Cologne Dom and Peter Zumthor's Kolumba Museum, which is itself builds upon an addition by Bohm over very ancient ruins.
Bohm's churches are somehow both crystalline and raw, weightless and yet massive. Concrete forms appear to reference structural notions: beams, buttresses, vertical supports, but their geometries twist, pivot and rotate in a manner almost similar to Gerrit Rietveld's Schroeder House. It seems like a Structural Expressionism - De Stijl hybrid. I find the effect incredibly beautiful.
The Kolumba museum allows for unexpected interactions between texture, light, and mass. Massive masonry walls suddenly give way to perforation and become a brick screen, allowing a grove-like dappling of light within the space, which itself is supported by a slender forest of piloti. The effect is to combine the appearance of a massive exterior with a floating and weightless expansive interior with no sense of heaviness.
I find a fascinatingly playful inversion of mass and lightness within all three buildings. Of course, the Cologne cathedral--with its flying buttresses, incredible mass, and dizzying, soaring interiors is a classic example of the Gothic's preoccupation with this relationship. The very different means through which theses inversions of lightness and mass occurs in each building is what interests me most. Bohm takes massive, raw concrete structures and adds an element of geometric idiosyncracy to structural elements to produce an abstract weightlessness. Zumthor produces a grove which seems to only loosely bound the interior space. Structural piloti are scattered about like trees while walls become dappled screens, allowing the ceiling to hover.