Folder: S.F. Bridges-Bay-Construction-Towers.
On back: "SAN FRANCISCO-OAKLAND BAY BRIDGE; Walter G. Swanson; 500 Sansome St. - GA rfield 1415. File 900.11 B-12/AA. VIEW OF TOWER W-3, SHOWING MAJOR STEEL WORK IN PLACE AND ERECTION OF GUY DERRICK ON TOP STRUT OF TOWER IN PROGRESS."