A church, before being appropriated for something beyond its original purpose, needs to undergo a ritual called “profanation.” The procedure is a sort of reverse engineering of the initial consecration. What once belonged to a god is handed back to human life. “And if ‘to consecrate’ (sacrare) was the term that indicated the removal of things from the human law, ‘to profane’ meant, conversely, to return them to the free use of men,” writes Giorgio Agamben. In the early 1950s, architect Dominikus Böhm was asked to build a church in the village of Kalscheuren, on the outskirts of Cologne. He let his son, Gottfried Böhm, actualize his preliminary design. (The younger Böhm would later become famous for his sculptural, crystal-shaped churches, and would be the first German architect to receive the Pritzker prize.) In Kalscheuren, slim pillars around the outside of a circular hall hold a flat, mushroom-shaped roof that makes the building look like a concrete model of a Mongolian yurt. Some consider it one of the most important postwar churches in the Rhineland. Yet, the fame of the monument did not prevent Catholicism’s decline, and in 2006, on May 25, 50 years after its consecration, the last service took …