First Avenue South Bridge
The First Avenue South Bridge is a pair of double-leaf bascule bridges built between 1956 and 1998 that carry State Route 99 over the Duwamish River about three miles (5 km) south of downtown Seattle, Washington. The present day northbound span was built in 1956 to connect the industrial areas northeast of the Duwamish to the residential neighborhoods to the south and southwest.
Source: Wikipedia — First Avenue South Bridge (CC BY-SA 4.0)