The Beyeler Foundation or Fondation Beyeler with its museum in Riehen near Basel owns and oversees the art collection of Hildy and Ernst Beyeler that was built up by the couple over five decades and placed under the aegis of the foundation in 1982. The collection was first publicly exhibited in its entirety at the Centro de Arte Reina Sofía in Madrid in 1989. By building Renzo Piano's museum structure in 1997, the Beyeler Foundation made its collection permanently accessible to the public. Some 200 works of classic modernism reflect the views of Hildy and Ernst Beyeler on 20th-century art and highlight features typical of the period from Claude Monet, Paul Cézanne and Vincent van Gogh to Pablo Picasso, Andy Warhol, Roy Lichtenstein and Francis Bacon. The paintings appear alongside some 25 objects of tribal art from Africa, Oceania and Alaska. A third of the exhibition space is reserved for special exhibitions staged to complement the permanent collection. In 2006 approximately 340,000 persons visited the museum. Ernst Beyeler (*1921) died on February 25, 2010.