With some 13,000 artworks, primarily by European and American artists, the modern art collection occupies , of gallery space and contains many iconic modern works. Cornerstones of the collection include Picasso's portrait of Gertrude Stein, Jasper Johns's "White Flag", Jackson Pollock's "Autumn Rhythm (Number 30)", and Max Beckmann's triptych "Beginning". Certain artists are represented in remarkable depth, for a museum whose focus is not exclusively on modern art: for example, ninety works constitute the museum's Paul Klee collection, donated by Heinz Berggruen, spanning the entirety of the artist's life. Due to the Met's long history, "contemporary" paintings acquired in years past have often migrated to other collections at the museum, particularly to the American and European Paintings departments.