Your walk follows the boulevard that has served as San Francisco's front door since the city was founded. The Embarcadero — from the Spanish embarcadero, a place to embark — traces the eastern edge of the original San Francisco peninsula along the shore of the bay. Before the Gold Rush, this shoreline was a natural cove called Yerba Buena Cove, with a sandy beach where supply ships anchored.
When gold mania hit in 1849, ships arrived faster than they could be unloaded; crews deserted to join the rush; and hundreds of abandoned vessels were eventually used as building foundations or fill for the new city. The entire Financial District east of Montgomery Street sits on this fill, and in earthquakes the buried ships and bay mud still liquefy and shift. The Embarcadero was dominated from 1959 to 1991 by an elevated freeway, the Embarcadero Freeway, which cut the city off from its waterfront with a double-deck concrete barrier.
When the 1989 Loma Prieta earthquake damaged the freeway, the city chose not to rebuild it — a decision that was bitterly controversial at the time and is now universally celebrated. The palm-lined boulevard and the restored Ferry Building are the direct result of that earthquake.