Photographer's notes: "View from the Nevada bridge deck down to the Nevada side arch segments and Colorado River." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "View from the Nevada bridge deck down to a Nevada side arch segment and Colorado River." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "View from a narrow side canyon used by the lower access road down to the dam. Note: This is one of the few photographs where I supplemented existing light by adding a flash to give the cliff on the right and the road some detail." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "Final concrete pour, which formed the keystone of the arch and completed its structure. Note: This photograph required a very last minute rush trip from Santa Fe to the Bridge. I got the call in the early afternoon and arrived to shoot just at sunset." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "Aerial view, April 10, 2012. Note: I was commissioned to photograph over the bridge and dam in April 2012, more than a year after my project was complete." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "Aerial view, April 10, 2012. Note: I was commissioned to photograph over the bridge and dam in April 2012, more than a year after my project was complete." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "Workers pour concrete for the barrier that will eventually separate traffic from pedestrians. Tub girders are in position on the Nevada side bridge deck for eventual installation over the arch and piers, February 2, 2010." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge