Chichen Itza was a center of pilgrimage for the ancient Maya for over 1,000 years. The Sacred Cenote (a large natural well or limestone sink hole) was holy to the ancient Rain God "Chac". About 987 the ruler of the Toltec people of central Mexico came here, and with his Maya allies made Chichen Itza the most powerful city in the Yucatan. The ruler called himself "Kukulcan", the name of the Mesoamerican Feathered Serpent deity (also known as "Quetzalcoatl") and Chichen Itza became a center for worship of that god as well. More buildings were built here in a mixture of Maya and Toltec styles. About 1221 the Maya revolted against the rulers of Chichen Itza. The city was not abandoned, but as political power shifted elsewhere it declined and no major new buildings were constructed. Chichen Itza remained a place of pilgrimage for the Maya until it was conquered by the Spanish Conquistadors in the 16th century. The structures of Chichen Itza were overgrown with jungle and slowly decayed until major archaeological projects began in the 1920s. Since then, more of the ancient structures have been cleared and restored and more and more tourists come to visit.