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

Photographer's notes: "Aerial view of bridge and the hairpin turn of the old Nevada road, June 30, 2009." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "The dirt road leading from the Lower Access Road to the Hoover Dam Police shooting range plays off of the arch formed by the bridge construction, June 30, 2009." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge