El Castillo - Xichen Itza, Yucatan, Mexico
When the Franciscans arrived at Xichen Itza and witnessed the Mayans practicing their acts of faith - worshiping snakes as a sign of new life (as they shed their skin annually) and practicing human sacrifice - they were horrified. The Franciscans destroyed the temples, as you see here on two sides of El Castillo, removing bricks. The Franciscans then used those bricks to build a Catholic mission a short distance away. Two sides of El Castillo remain unrestored due to the fact that the bricks were used to build the mission that still stands today in the nearby village of Piste.