Seattle's Alaskan Way Viaduct. The Viaduct is several miles long and runs along the waterfront in Seattle. Its dual levels were built 55 years ago. (Slightlynorth)

America's Infrastructure: The Alaskan Way Viaduct

Seattle's Alaskan Way Viaduct. The Viaduct is several miles long and runs along the waterfront in Seattle. Its dual levels were built 55 years ago.

Credit: Slightlynorth