The Zion Mt. Carmel Tunnel, a 5,613-foot-long tunnel and the longest vehicular tunnel in the National Park System, was blasted through the towering sandstone cliffs above Pine Creek Canyon. Its construction required extraordinary access through cliff-face galleries for blasting and excavation. The tunnel and the 25-mile-long highway, completed between 1927 and 1930, promoted the NPS-Rustic style of engineering and landscape architecture used throughout the National Park System.