The first lesson at Chichén Itzá is not written on a sign. It is in the way people slow down when El Castillo comes into view.

People do not all stop at once. Someone is still adjusting a hat, someone is reaching for a water bottle, and a guide is talking over the low buzz of the plaza. Then El Castillo clears the crowd, and the mood shifts in that quiet way old places sometimes manage. A finger goes up toward the steps, then toward the shadow line, then toward the pyramid itself, sitting calmly in all that open space.