Burhan Dogançay became famous the world over with the series of photographs he created--often at dizzying heights--during the renovation of the Brooklyn Bridge in New York City. But the main focus of his photographic career has been the series "The Walls of the World," the artist's intensive, exhaustive interrogation of walls. Through travels to more than 100 countries, among them Vietnam, Sri Lanka, Bahrain and Cuba, Dogançay has captured the exceptional and the trivial aspects of these surfaces in more than 20,000 photographs, a selection of which appear here.