When I first encountered the bridge at Hoover Dam in March 2009, it immediately captured my imagination. The photo essay, which is evolving from this initial encounter, allows me to meld photographic and aesthetic sensibilities with a reawakened sense of childhood curiosity and awe. Photographically, the bridge as subject is creatively and technically challenging, dynamic and transitory. Construction of the bridge downstream from Hoover Dam is unique both for its historical importance, by its proximity to the dam, and for its technical achievement, bridging the Black Canyon over the Colorado River with the longest concrete arch span in North America.