Wikipedia describes the Hanover Street Bridge:

The Hanover Street Bridge — officially, the Vietnam Veterans Memorial Bridge — is a bascule bridge crossing the Middle Branch of the Patapsco River along Hanover Street (Maryland Route 2) in Baltimore, Maryland, USA. The bridge was built to replace the mile-long “Long Bridge” built by Richard Cromwell in 1856 to move products from his orchard in Anne Arundel County to downtown Baltimore.

The Maryland State Highway Administration describes the bridge, writing:

At the time of its completion, the Hanover Street Bridge, now known as the Vietnam Veterans Memorial Bridge, was the largest reinforced-concrete bridge in the state. Its thirty-eight spans reach 2,290 feet across the Middle Branch of the Patapsco River in Baltimore’s Outer Harbor. Designed by the former Baltimore and Ohio engineer John E. Greiner for the Maryland State Roads Commission, the Beaux Arts-style bridge vastly improved transportation in Baltimore at a time when trucks began to take precedence over the steamboat in getting goods to market. The four concrete towers, positioned at the corners of the steel draw span, give the bridge a classical symmetry.

Learn more about the Hanover Street Corridor Study (Includes the Vietnam Veterans Memorial Bridge) from the Baltimore City Department of Transportation.