Northern Yucatán is arid, and the rivers in the interior all run underground. There are two large, natural sink holes, called cenotes, that could have provided plentiful water year round at Chichen, making it attractive for settlement. Of the two cenotes, the “Cenote Sagrado” or Sacred Cenote (also variously known as the Sacred Well or Well of Sacrifice), is the most famous. According to post-Conquest sources (Maya and Spanish), pre-Columbian...