The Palace of Fine and Decorative Arts, also known as Building 3, on Treasure Island in San Francisco Bay, California, was an aircraft hangar constructed in 1938 for Pan American World Airways' trans-Pacific Clipper services, and then modified for the 1939-40 Golden Gate International Exposition. Building 3 was one of a pair of identical hangars built to house Pan American's flying boats at the south end of the island. Building 1 was to be the airline's terminal building, and Buildings 2 and 3 would house the aircraft. For the exposition, these buildings were converted to exhibition halls, surrounded by a complex of temporary structures. At the end of the exposition all structures but Buildings 1, 2 and 3 were to be torn down to make way for the development of the reclaimed land as an airp