The Golden Gate International Exposition of 1939-1940 was San Francisco's celebration of its two new bridges -- the Golden Gate and the Bay Bridge. The fair needed a site, and the city built one: Treasure Island, created by dumping millions of cubic yards of fill material into the bay. The exposition featured Art Deco buildings, international pavilions, and the optimistic vision of a city that had just connected itself to the rest of the Bay Area by bridge. When the fair closed, the island was supposed to become San Francisco's airport. Pearl Harbor changed those plans.

The Navy operated Treasure Island as a major Pacific Fleet logistics and training facility for 55 years. During World War II, the station processed hundreds of thousands of sailors and Marines heading to the Pacific theater. The base continued operating through the Cold War, serving as a training center, an administrative headquarters, and an occasional film and television location. The station was decommissioned in 1997 as part of the post-Cold War base closure process.

The island's transition from military base to civilian use has been complicated by environmental contamination. Decades of Navy operations left behind hazardous materials, including radioactive materials from a radiological defense laboratory that operated on the island. Cleanup efforts have been ongoing for years. Despite these challenges, the island is being developed as a mixed-use neighborhood with housing, parks, and commercial space. The Art Deco buildings from the original fair -- including Building 1, the former terminal -- are being preserved as part of the development.