In this image of Izamal’s great pyramid, Kinich Kak Mo, the colossal head of a Maya figure looms high above the expedition’s naturalist, Dr. Samuel Cabot, Jr., and an unnamed Maya attendant.

Then, in 964, the Itzás, a Maya-speaking people from the Petén rain forest around Tikal, moved into the city. Archeologists have fully explored only about 20 or 30 of several hundred buildings ...