The Golden Gate International Exposition was one of the grandest parties in San Francisco’s history. It was so big, in fact, an island was built for it.

Now, eight decades later, we’re publishing photos of the 1939-40 Treasure Island bash taken from negatives that had been collecting dust for decades in an old, beat-up cardboard box in The Chronicle’s basement. Images of the fair’s Tower of the Sun and other attractions are regularly published, but these archive finds show perspectives that few people have ever seen.

Held amid the afterglow of the premieres of the Bay Bridge and Golden Gate Bridge, the exposition was a world’s fair that opened Feb. 18, 1939, and drew 10 million visitors to Treasure Island. The theme was “Pageant of the Pacific,” and the event featured fantastical architecture and a fabled Gayway boulevard of amusements.

Looking back at the fair in 1989, Chronicle book reviewer Harre Demoro wrote: “The exposition, with its colorful, fanciful Art Deco buildings, was a last fling of innocence. Gawking visitors marveled at microwave ovens and stared at early television sets.”

With World War II on the horizon, and the Depression still stunting the economy in San Francisco and across the nation, the Golden Gate International Exposition was a fanciful escape for tourists and residents of the Bay Area.

The aerial photos pulled from the archive show a gleaming, bustling island, but it wasn’t only a hub for shiny buildings and futuristic appliances. It hosted one of the two regionals for the first NCAA Basketball Tournament, for instance. And visitors who wanted to get off the island could see the city by the bay and its bridges by driving the 49-Mile Scenic Drive, a route created for the expo that’s still a tourist draw.

The Golden Gate International Exposition was set to end in October 1939, but its popularity and huge attendance numbers led officials to reopen the doors for an encore on May 25, 1940. It closed for good Sept. 29 of that year. The U.S. Navy and Army moved in and took over Treasure Island, creating bases for military personnel.

Chronicle columnist Carl Nolte, writing about the island in 1996, summed up the fair nicely: “To another generation, Treasure Island was ‘The Magic City,’ a world’s fair that sparkled for a few months like a multicolored jewel in the middle of San Francisco Bay.”