Postmodern architecture is not necessarily a style, but an approach; therefore, postmodern buildings will not necessarily look like one another, but may share some characteristics. One of the key postmodern architects is Robert Venturi (1925-), a Philadelphia-born architect who believed that the urban environment was too complex to be uniform. In 1966, he wrote Complexity and Contradiction, where he responded to modernist architect Ludwig Mies van der Rohe’s statement, “less is more” by declaring “less is a bore.” Venturi’s architectural style is infused with various architectural styles from history. A good example is the Vanna Venturi House, completed in 1964 and built for the architect’s mother. The Vanna Venturi house is at once complex and simple, serious and playful. It has a solid foundation and an angled roof, and evokes a sense of the traditional farmhouse—but not quite. This ethereal lack of uniformity is characteristic of postmodernism. Frank Gehry is also a well-known postmodern architect who built the Disney Concert Hall in Los Angeles, which opened in 2003, and the Guggenheim Museum of Modern Art in Bilbao, Spain, in 1997. His work is often constructed of highly polished stainless steel made up of distorted planes that form a complex, curvilinear design—a chaotic style that can be described as deconstructivist.