In the first half of the 20th century, collector and educator Albert C Barnes amassed a remarkable trove of artwork by Cézanne, Degas, Matisse, Renoir, Van Gogh and other European stars. Alongside, he set beautiful pieces of folk art from Africa and the Americas – an artistic desegregation that was shocking at the time. Today's Barnes Foundation is a modern shell, inside which is a faithful reproduction of Barnes's original mansion (still in the Philadelphia suburbs).

The art is hung according to his vision, a careful juxtaposition of colors, themes and materials. In one room, all the portraits appear to be staring at a central point. Even more remarkable: you've likely never seen any of these works before, because Barnes' will limits reproduction and lending.