Deep in the Gila mountains, a fast-moving stream of water shoots down a narrow slot canyon. Aptly named Whitewater Canyon, it is traversed by a series of metal bridges. From this elevated catwalk system, visitors can enjoy the running water, misty air, lush vegetation, and steep canyon walls. This beautiful canyon trail actually began with a utilitarian purpose. In the 1890s, a nearby gold and silver mill required a steady supply of water to power its machines. Workers built a pipeline from Whitewater Canyon, and a series of catwalks to…