The Guggenheim Museum is Bilbao's architectural showpiece. The building, designed by Frank Gehry (who was awarded the Pritzker Architecture Prize in 1989), is considered a masterpiece, with its amazing intertwined curves and its walls of yellow limestone, glass and titanium, which invite an extraordinary play of light. It houses one of the greatest collections of 20C art in the world, from the classic avant-garde to Abstract Expressionism, Pop Art, and more modern trends.