Photographer's notes: "Evening aerial view of the dam and bridge. Twelve tub (box) girders spanned the central pier caps of the bridge forming part of the substructure for the roadbed. Note: This photo was taken well after sunset and was only possible because of the state of digital technology in 2010." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "A solitary ladder extends from the arch to a walkway between tub girders below the road deck, April 13, 2010." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "View from the river up to the Arizona side. Deck construction was still in progress. Note: This was the only time I was given access to this particular point of view on the Arizona side beneath the bridge." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "View from the river up to the Arizona side. Deck construction was still in progress. April 14, 2010." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "View up to the Nevada side from the Arizona side of the powerhouse with the first of the final four tub girders installed, April 15, 2010. Note: Someone was the first person to walk across the span completed when this girder was installed. I never learned who that person was." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "The second of the final four tub girders is flown into position via the highline crane, April 15, 2010." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "Ironworkers from Arizona Local 75. California/Nevada Local 433 and management pose for snapshots before the final tub girder is flown into position by the highline crane, April 15, 2010." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge