The numerals “1915” that were emblazoned on the tower of San Francisco’s Ferry Building harkened back to a time when the devastation of the great earthquake and fire and a turn-of-the-century can-do spirit combined to create an event that amazes still.

Centennial celebrations of the 1915 Panama-Pacific International Exposition have occurred around the city, but documentary accounts of the exhibits, the personalities, and the architecture are no farther away than your computer screen.

In 1962 KPIX-TV aired a “nostalgic visit” to the fair, which occupied more than 600 acres and ran from February to early December of 1915. The program, titled “The Innocent Fair” and archived at San Francisco State University’s Bay Area Television Archive, includes footage of the fair shot on nitrate film, an early and highly flammable material.

Blurry and shaky at times, the images provide views of wonders such as the Fountain of Energy, the Tower of Jewels and the palace of Fine Arts – the only exposition building still standing. Viewers see celebrities and VIPs of the era, including Thomas Edison, President William H. Taft, Charlie Chaplin and film star Mabel Normand.

The KPIX documentary was produced by Ray Hubbard, described by the Los Angeles Times in a January 2000 obituary as a “pioneering television producer and broadcasting executive who believed the medium should be an engine for social change.” Hubbard, who lived in Kenwood, was 75.

His work had a lasting impact on the city. According to the Times, “The Innocent Fair” was “credited with saving San Francisco’s crumbling Palace of Fine Arts from demolition.”

The documentary owes its existence to Lee Mendelson, the associate producer who went on to fame as producer of scores of the iconic Charlie Brown television specials.

Mendelson had studied and later taught at Stanford University. The university’s alumni magazine gave this account of his extraordinary find:

“(S)trolling through the village of Tiburon, across the bay from San Francisco, he stumbled across an antique shop and discovered a box of nitrate film with footage of the 1915 San Francisco World’s Fair. That auspicious discovery became the core of his first documentary, The Innocent Fair.”

In December 2014 C-Span aired a scholarly lecture about the fair by architectural historian Laura Ackley, author of “San Francisco’s Jewel City: The Panama-Pacific International Exposition of 1915.”

On her website Ackley describes the exposition’s “powerful impact locally and nationally, influencing taste in art and design, and introducing a number of new technologies to its more than 19 million attendees. The fair’s midway, dubbed ‘The Zone’ hosted rides, historical re-creations and shows, not all of them wholesome. The exhibit Palaces and their adjacent courts showcased new ideas in landscape design, architectural color and an innovative illumination featuring spectacular effects including the ‘Electric Kaleidoscope’ and the ‘Great Scintillator.’ ”

For sheer entertainment, watch this episode of the American Coaster Enthusiast’s “The Lost Parks of Northern California.”

Conceived by Kris Rowberry, the series covers the demise of iconic spots such as Santa’s Village in Scotts Valley, Frontier Village in San Jose and the Manteca Waterslides. But the 1915 exposition was different – and not just in size and scope. The fair, he says, “was built to be destroyed.”

Not everything was lost, though, as Rowberry shows you vestiges of the fair, including the exposition pipe organ, stored in a basement at Civic Center Plaza.