The "scenic route" in southwestern Colorado means the San Juan Skyway, a 236-mile loop created by U.S. Routes 550 and 160 and State Routes 62 and 145. The Skyway wends through glacial valleys and over high passes between some of the most breathtaking, ice-sculpted peaks in the Rocky Mountains. Native Americans, pioneering mountain men, miners, and railroaders inhabited these slopes. Although the Skyway towns of Durango, Silverton, Ouray, Ridgway, Telluride, Rico, Dolores, and Cortez were first connected by wilderness trails and railways, the loop's final modern section of highway between Coal Bank and Molas Passes was completed in the 1940s. The rugged San Juan Mountains were the backdrop for exploits by Butch Cassidy and Wyatt Earp, but, as author Frederic B. Wildfang notes, the scenery is also "a syllabus for a course in geology."