Alaskan Way Viaduct (Defunct)

Built in 1952 and opened on April 4, 1953, the Alaska Way Viaduct was replaced with a double-decked tunnel beneath downtown, which was completed on January 11, 2019 and opened on February 15, 2019. The reason for replacing it was the Loma Prieta Earthquake that struck the San Francisco Bay Area in 1989, causing the similarly-designed Cypress Street Viaduct to collapse, killing 42 motorists, as well as the 2001 Nisqually Earthquake, which caused damage to the viaduct requiring nearly $USD 15 million in emergency repairs. Since Seattle is also on the west coast, and is no stranger to earthquakes, it was considered a wise idea to replace the viaduct with a tunnel and urban boulevard, giving a better view of Puget Sound to downtown, once again.