Black Canyon of the Colorado the Nevada side of the canyon is the Sauna Cave. This cave was drilled by miners working on Hoover Dam while it was being constructed. It is a deep cave with calcium carbonate crystals on the walls. At the end of the cave is a hot spring, which causes temperatures in the cave to reach . One prominent canyon that splits from this canyon south of the Hoover Dam is Boy Scout Canyon. Boy Scout Canyon has water running through it that is warmed from a geothermal source. On the Arizona side of the river, there are several large hot
Glen Canyon Dam Bridge Glen Canyon Dam Bridge The Glen Canyon Bridge or Glen Canyon Dam Bridge is a steel arch bridge in Coconino County, Arizona, carrying U.S. Route 89 across the Colorado River. The bridge was originally built by the United States Bureau of Reclamation to facilitate transportation of materials for the Glen Canyon Dam, which lies adjacent to the bridge just upstream. The two-lane bridge has an overall length of with a deck above the river, making it the one of the highest bridges in the United States. The bridge was the highest arch bridge in the world when completed in 1959.