In 1940, Heinz Berggruen was on his honeymoon in Chicago when he bought his first work of art: a watercolor by Paul Klee, for $100. A decade later, he opened an art gallery in Paris, where figures such as Baron Hans Heinrich Thyssen-Bornemisza—the future namesake of the Madrid museum—were among his visitors. Over the years, Berggruen amassed 165 works by 20th-century masters—Braque, Matisse, Klee, Giacometti—before eventually returning them to his native Germany after the Nazi era. This exhibition presents 50 masterpieces by two of his earliest passions, Klee and Picasso, on loan from the museum that bears Berggruen’s name. —Elena Clavarino