Lucerne, Switzerland: Rosengart Collection Museum

Siegfried Rosengart was an art dealer who lived from 1894 to 1985. Along the way he became friends with Pablo Picasso and Marc Chagall. Before he knew, he had quite a collection of works from some very famous artists.

From there, the collection - which included a large amount of art from Paul Klee - went on public display in 2002. A building originally used by the Swiss National Bank was converted into an art gallery. Whole floors are devoted to Picasso and Klee, but the top floor is used for everyone else.