At the time of the 1989 Loma Prieta earthquake, the Cypress Street Viaduct double-deck segment of the Nimitz Freeway collapsed, killing 42 people. The old freeway segment had passed through the middle of West Oakland, forming a barrier between West Oakland neighborhoods. Following the earthquake, this section was rerouted around the perimeter of West Oakland and rebuilt in 1997–2001. The east span of the San Francisco–Oakland Bay Bridge also suffered damage from the quake when a 50-foot (15-m) section of the upper deck collapsed onto the lower deck; the damaged section was repaired within a month of the earthquake. As a result of Loma Prieta, a significant seismic retrofit was performed on the western span of the Bay Bridge. The eastern span has now been replaced with a dramatic single-tower self-anchoring suspension span.