Photographer's notes: "A pair of columns support the girders and bridge deck, Nevada side, evening, May 20, 2009." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "Upstream view of the bridge and dam. The growing arch segments on the Nevada and Arizona sides of the canyon moved toward their rendezvous over the Colorado River." 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 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 looking downstream of the bridge arch construction, the Nevada side hairpin turn of the old road, and the Colorado River, June 30, 2009." 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

Photographer's notes: "View upstream of arch construction and the traveler forms used on each side, June 30, 2009." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge