Editor's Note: This article was originally published in June 2012 and has been updated with the most recent information.

After the construction of the Bay Bridge in 1933, San Francisco began considering duplicating the bridge and running a second one further south across the bay. Enter Frank Lloyd Wright, the famed organic architect whose idea and design for a second Bay Bridge never came to fruition.

The noted architect hated the idea of a second steel structure similar to the San Francisco–Oakland Bay Bridge. Partnering with engineer Jaroslav J. Polivka, Wright proposed a concrete "Butterfly Bridge,” spanning from Army Street (now Cesar Chavez) and Third Street to its eastern terminus on Bay Farm Island, just north of the Oakland Airport.

Wright and Polivka saw steel truss bridges as extravagant and obsolete, so the design was all reinforced concrete, resting on a series of giant hollow almond-shaped piers—which they claimed to be earthquake-proof construction. Long curved arms would carry six lanes of traffic and two pedestrian walkways, supported by two arches connected by a butterfly-shaped garden park (!) as “a pleasant relief and perhaps a stopping point for the traffic.”

During a May Day appearance at San Francisco Civic Center in 1957, Wright unveiled his bridge to the public for the first time. His presence at the event, sponsored by the city’s Planning and Housing Association, drew a rapt, large crowd.

The San Francisco Chronicle (via Frank Lloyd Wright and San Francisco) described the event:

Frank Lloyd Wright...unveiled a model of his “butterfly” bridge for San Francisco Bay last night with a flight to Wrightian rhetoric as soaring as the bridges great arches. “Here is your bridge: Steel the sinews, buried in the flesh—concrete! A bridge for all time, no upkeep ever needed,” he orated. The audience that jammed the San Francisco Museum of Art [then in the War Memorial Veterans Building] to see and touch the 16-foot model of the bridge, laid across a pool of mirrors, was appropriately uplifted. The 535 seat in the main auditorium were sold out...another 500 listeners applauded Wright’s words in an overflow gallery, and an estimated 500 more sprawled on the marble floors with their ear cocked to amplifiers. Wright called his bridge “this concatenation—this wedding of two materials—an eternal bridge, in which the water becomes with the bridge itself a great element of beauty ... We can’t go on building bridges that are the equivalent of poles and wires.”

Wright finished his speech with this incendiary tidbit:

“You are citizens, all of you, aren’t you? Divorce the bridge from politics. Stop worrying about Oakland. Get out and build it yourselves.”

Alas, the Butterfly Bridge project lost steam after plans for the underwater—and vastly more important—Transbay Tube were unveiled, a project that connected BART from San Francisco to Oakland.

However, the idea of a Southern Crossing bridge hasn't been abandoned—a bond measure on the ballot in 1972 would have funded a planned crossing from Hunters Point and Alameda, but voters rejected it.

A post shared by Brock Keeling (@brockkeeling) on Dec 8, 2017 at 1:37pm PST

Another push in the 1980s died after facing opposition from environmental groups.

Sen. Dianne Feinstein revived the Southern Crossing proposal in 2000, but studies found it would cost at least $8.2 billion. But in 2010, the Bay Area Toll Authority voted to spend up to $400,000 to conduct two-year study on a bridge between Interstate Highway 238 in San Lorenzo and Interstate Highway 380 in San Bruno.

Most recently, Sen. Feinstein and East Bay Congressperson Mark DeSaulnier penned a letter to the Bay Area Metropolitan Transportation Commission, urging them to construct an additional bay bridge in order to relieve traffic congestion.

Who knows? Maybe Wright’s concrete Butterfly Bridge will—at last—take flight.