The Fillmore Street Tunnel was a proposed double-bore tunnel approximately long in San Francisco, California which would have carried Fillmore Street and a new streetcar line underneath Pacific Heights and Russian Hill. The proposed tunnel would have connected the Western Addition and Fillmore Districts, near the south portal at Sutter Street, with Marina and Cow Hollow, near the north portal at Filbert Street. One tunnel would have been reserved for railroad and pedestrian traffic, while the parallel tunnel would have been for vehicles. The tunnel was planned, along with the contemporary Twin Peaks and Stockton Street Tunnels, to serve the traffic that was anticipated from the 1914–15 Panama–Pacific International Exposition. The tunnel was first announced in early 1912. However, the preparation of detailed plans and permits delayed the estimated start of construction to July 1914, which meant the tunnel could not be completed in time to service the Exposition, and the project was killed in September 1913. History Shortly after the directors of the Panama–Pacific International Exposition (PPIE) selected a site in the Harbor View district, the merchants along Fillmore formed the Fillmore Street Improvement Association (FSIA) to study the possibility of constructing a tunnel along Fillmore Street. The FSIA hired an engineer to prepare preliminary plans and estimates, and FSIA members visited similar contemporary tunnels in Los Angeles to obtain practical advice; an official announcement was scheduled for early January 1912. Fillmore Street had come into prominence following the 1906 San Francisco earthquake, which forced many businesses to relocate from Market to Fillmore. In addition to the temporary benefit to speed traffic to and from the PPIE, the Fillmore Tunnel was expected to spur development along the northern waterfront for trade via the Panama Canal and to shorten the commute from the Marin County suburbs. The Fillmore Street Tunnel and a rival parallel route under Steiner Street, one block to the west, were compared in January 1912. While Steiner Street proponents declared their tunnel would be shorter and less expensive, the FSIA argued that tradition and existing streetcar routes favored their proposal. They pressed the case for Fillmore in a front-page editorial published in January 1912, and the editors of the San Francisco Call agreed with FSIA. By February, the Fillmore alignment was being favored over competing parallel routes along Steiner, Pierce, and Divisadero; however, the land and tunnels committee of the San Francisco Board of Supervisors delayed their