Rock pillar introduction: Bryce Canyon was not eroded by the central water flow, so it is not technically a canyon. It was formed by sourceward erosion digging out the Cenozoic strata of the Pangsagunt Plateau. This erosion process created numerous exquisite and colorful pointed rock pillars called pillars, which can be as high as 200 feet (60 meters). A series of amphitheaters stretch over 20 miles (30 kilometers) within the park. The largest of these is the Blythe Amphitheater, which is 12 miles (19 kilometers) long, 3 miles (5 kilometers) wide and 800 feet (240 meters) deep.