Suddenly I made the connection. The sloping walls of the ball court that lay below me were identical, in their angle and method of construction, to the walls in the sub-basement of the Sanctuary of the Virgin in Izamal. According to Gus, the church had been built on top of an ancient Mayan building of some kind. I now knew what that building had been: a ball court, older and much more unique than the one below. I remembered the flat, round stone on which Gus had sat while we were resting in our flight from the Azzie soldiers—the one with the skulls and glyphs carved around its edge and the hole at its center. Someone who didn’t know its history might take it to be goal ring, broken free of its mount on the wall and left where it lay when the base of the tlachtli was turned into the sub-basement of the church. But this stone was unbroken and had been set into the floor of the ball court itself. Positioned dead center, at the spot where the four quarters of the playing field met.