The water rushing over the Basaltic Prisms of Santa María Regla make the ancient pillars look especially surreal. The columns are polygonal and vary in height from 100 to more than 150 feet tall. They contain a ravine whose water flows from the San Antonio Dam, often times causing a rainbow to form at the base of two waterfalls. The tourist attraction is located in Hildago, Mexico, and can be enjoyed via walkways and hanging bridges.