Photographer's notes: "Ironworkers fabricate rebar forms on the Arizona side, then the forms were transported via highline crane into position for the next segment of arch construction, June 29, 2009." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "This telephoto view of the Nevada side arch construction reveals the complexity of the process, June 29, 2009." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "Evening view of the arch segments nearing their rendezvous over the Colorado River." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "A concrete pour in process for a section of the arch construction, view from Nevada parking lot near Visitors' Center, June 29, 2009." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "Aerial view of Lake Mead, Hoover Dam, and the bridge under construction with reflection of the bridge in river below, June 30, 2009." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "Aerial view of the bridge, dam and Lake Mead." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "Aerial view of a motor boat on Lake Mead near the mineral deposit banding that revealed the lower level of the Lake Mead reservoir, June 30, 2009." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge