Photographer's notes: "Afternoon aerial view of the river, bridge, dam and Lake Mead, January 14, 2011." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "Afternoon aerial view of the river, bridge, dam and Lake Mead, January 14, 2011." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "A late afternoon shadow reveals the connection between the bridge and dam. Note: This was one of the last photographs from the bridge project. When I headed back to the airport, the project's photography was complete." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "Aerial view of the bridge's shadow against the face of the dam with half of the bridge's deck along the bottom edge of the frame, January 14, 2011." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "With the bridge complete and open, the bridge, dam and lake now share the Black Canyon." Site Name: Mike O'Callaghan-Pat Tillman Memorial Bridge

Photographer's notes: "With the bridge complete and open, the bridge, dam and lake now share the Black Canyon. January 14, 2011. Note: This is the uncropped version of this photograph. I chose to crop out the horizon for use in the book and exhibition." 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