SAN DIEGO » A hundred years ago, San Francisco had something to prove.

Its leaders wanted the world to know they had rebuilt since the earthquake and fires of 1906, and they wanted to woo the travelers and commerce that would be headed west through the just-completed Panama Canal. So they decided to throw a global party.

San Diego had something to prove, as well. It had about 40,000 residents — about a tenth of San Francisco’s population — but no cable cars, no gold rush glamour, no Mark Twain quotations. And a Mexican civil war was simmering just south in Tijuana. But San Diego wanted tourists and ship traffic. Even after President William Howard Taft and Congress threw their support behind San Francisco, San Diegans pressed ahead with plans for their own exposition.

The result: competing expos, assembled as World War I was beginning to tear Europe apart. This had all the makings of a civic disaster. Maybe two.

Yet both shows went on. In a state with fewer than 3.4 million people, they together tallied 22 million visitors. The city with the brighter lights and bigger crowds, however, isn’t the one that ended up with the larger architectural legacy.

Once San Francisco had federal backing for its Panama-Pacific International Exposition — defeating not only San Diego, but also a vigorous New Orleans bid — the local infighting began over where to put it. After flirting with the idea of Golden Gate Park, organizers decided to use 635 acres of lightly built marshland known as Harbor View, creating a bay-front playground just east of the Presidio and west of Van Ness Avenue. Nowadays it’s known as the Marina District.

Except for a chunk of the Presidio and a bit of Fort Mason, all this land was privately owned. The expo organizers leased it and set about building a temporary wonderland in grand Beaux-Arts style, with hundreds of statues and faux travertine by the ton.

The San Francisco expo ran Feb. 20 to Dec. 4, 1915. The expo’s central landmark was the Tower of Jewels, a 435-foot wonder encrusted with 102,000 cut-glass "jewels," surrounded by hidden lights. (The "Jewel City" theme had been suggested in a newspaper’s naming contest by Virginia Stephens, a 12-year-old black girl from Oakland.)

There was the Palace of Horticulture (with a glass dome larger than St. Peter’s Basilica in Rome), four 204-foot towers, a 638-room hotel (the Inside Inn), the Arch of the Rising Sun, a 7,000-pipe organ, a sprawling midway known as the Joy Zone, a 6-acre replica of the Grand Canyon, a 5-acre working replica of the Panama Canal, a pop-up factory making Levi’s jeans, a 15-foot-tall Underwood typewriter and a Ford assembly line turning out 18 Model T’s per day.

The Great Scintillator, a pier packed with 48 projector spotlights, stood near the fairgrounds for nine months, sending festive pastel-colored beams into the night sky and fog. To coordinate these displays, the expo hired a director of color, Jules Guerin, who envisioned "a gigantic Persian rug of soft melting tones" and told participating artists what hues they could and couldn’t use.

Despite many cancellations as World War I deepened in Europe, 21 nations sent representatives and materials for pavilions, as did 28 states and territories. (From Oregon: a Parthenon made of Douglas fir logs.) Neither Britain nor Germany put up pavilions, nor did Mexico.

But Thomas Edison, Henry Ford, Charlie Chaplin, Helen Keller and former President Theodore Roosevelt all came. Laura Ingalls Wilder, future author of the "Little House" books, marveled at a cow-milking machine. Ansel Adams, age 13, had a season pass and wandered the grounds daily, shooting photos with a Brownie box camera.

In all, nearly 19 million visitors turned out, a civic triumph for San Francisco by just about every measure. On the last day alone, 459,022 guests showed up.

And then it all but vanished. Buildings were leveled; materials were salvaged and sold for scrap. Real estate reverted to its owners. And much was scattered among new owners. The plaster sculpture "End of the Trail," by James Earle Fraser, a bowed depiction of a Native American on horseback that once stood in the expo’s Court of Palms, now graces the National Cowboy & Western Heritage Museum in Oklahoma City.

Among the significant structures, only one survived in its original location: the lagoon-adjacent rotunda and colonnades of the Palace of Fine Arts, which was bolstered by reconstruction in the 1960s. To see more of the 1915 expo in San Francisco, you must do some sleuthing — or visit during this year’s centennial exhibitions.

On the one hand, said Laura A. Ackley, author of "San Francisco’s Jewel City: The Panama-Pacific International Exposition of 1915," the event made money, gilded the city’s reputation and "changed the standard for architectural illumination worldwide." On the other, "it was so ephemeral. And the San Diego one lives on."

In the beginning, things didn’t look good for San Diego’s Panama-California Exposition. Organizers had far less money to spend, no federal blessing and plenty of discord.

Nationally acclaimed landscape architects John C. Olmsted and Frederick Law Olmsted Jr. signed on, then quit. So did a rising architectural star named Irving Gill.

Under the terms of a truce with San Francisco, San Diego had to leave the word "international" out of the name of its expo.

"At first it was a rivalry," said Iris Engstrand, a professor of history at the University of San Diego and curator of "San Diego Invites the World: The 1915 Expo" at the San Diego History Center. "But then they both realized they were both going to have a fair and they’d better cooperate."

San Diego organizers staked out a 640-acre chunk of City Park, renamed it Balboa Park and chose a Spanish Colonial design theme, allowing a wide berth for Baroque Mexican flourishes, Moorish tiles and stark mission arches.

The centerpiece would be the California Building with a soaring tower and a tiled dome designed by New York architect Bertram Goodhue. It would be permanent, as would a new bridge, an organ pavilion and a vast wooden botanical building neighbored by a pond.

An Indian village, complete with a facsimile of New Mexico’s Taos Pueblo, filled several acres. Seven U.S. states put up buildings. Five buildings held exhibits from the counties of California.

Then there was the Isthmus, a half-mile-long midway where visitors found the Temple of Mirth, the Sultan’s Harem, a Hawaiian village, a Chinatown and a 250-foot-long model of the Panama Canal.

Opening day was Jan. 1, 1915, about 50 days ahead of San Francisco’s. Two million people turned up in the first 12 months. Many San Francisco expogoers made side trips to San Diego, including Roosevelt, Edison and Ford. After the San Francisco expo closed, San Diego’s fair kept going. In fact, it got a commercial second wind by bringing in foreign exhibitors and concessionaires who were happy to delay their return to a warring Europe.

In September of the expo’s second year, noted Richard Amero in "Balboa Park and the 1915 Exposition," Dr. Harry M. Wegeforth was driving nearby when he heard the roar of a lion on display along the Isthmus. He turned to his brother Paul and said, "Wouldn’t it be splendid if San Diego had a zoo?" Soon it did.

By the time San Diego’s expo closed on Jan. 1, 1917, attendance had reached about 3.8 million over two years, about a fifth of San Francisco’s total.

But San Diego’s key buildings had been built to last — and on public land. Moreover, as the decades passed, three temporary structures along the Prado promenade (now known as the Casa del Prado, the Casa de Balboa and the House of Charm) were saved and eventually rebuilt near the remodeled House of Hospitality.

Thanks to that fair, Engstrand said, "San Diego became a little more popular, although it has never achieved, even today, the status of San Francisco."

Meanwhile, she added, Spanish Colonial architecture gained popularity in the West. In the course of their hosting chores, local leaders also forged ties that helped the city emerge as a Navy town.

By Christopher Reynolds, Los Angeles Times