There is little question about the shameful history of the Flick family. But taken as a body of work, the controversial art collection now on display in Berlin is a fascinating journey through the 20th-century’s artistic evolution. “Again and again, the visitor is faced with sexual symbols, violence and existential questions. Piles of objects serve as metaphors of the ephemeral and insane.” Still, it is clear there is no way for many Germans to view the individual works on display without being constantly reminded of the manner in which they were acquired.