West Oakland’s Cypress Street Viaduct, also called the Cypress Freeway or Cypress Structure, was a 3-mile (or 2 kilometer) elevated section of the Nimitz Freeway (Interstate 880) between 7th Street and 34th street, which collapsed during the Loma Prieta earthquake on October 17th, 1989.
The magnitude 6.9 earthquake caused the upper tier of the two-deck highway between 18th Street and 34th Street to fall on to the road deck below, with some parts collapsing entirely to the ground. The collapse crushed cars and their occupants, killing 42 people, two thirds of the total San Francisco Bay-area death toll from the earthquake.
It was not rebuilt, and the entire structure as far as 7th Street was demolished and the Nimitz Freeway rerouted. Cypress Street was renamed Mandela Parkway in honor of Nelson Mandela, and a landscaped median strip was created where the viaduct once stood. The Cypress Freeway Memorial Park honoring the victims is located at 14th Street and Mandela Parkway.