Perhaps nowhere are the forces of natural corrosion more substantial than at Bryce Canyon. Its wilderness of phantom-like rock spires, or hoodoos, attracts more than one million visitors a year. Many come down on trails that give hikers and horseback riders a close look at the fluted walls and sculptured summits. The park follows the rim of the Paunsaugunt Plateau. On the west are profoundly forested tablelands more than 9,000 feet high; on the east are the intricately engraved breaks that drop 2,000 feet to the Paria Valley. Many transient streams have eaten into the upland, forming horseshoe-shaped bowls. The biggest and most prominent is Bryce Amphitheatre. For millions of years water has imprinted, as it continues to, Bryce's jagged landscape.