Officials from the local provincial government explored Tikal in the mid-1800s, followed closely by the British and then by Harvard University. Archaeologists from the University of Pennsylvania began excavating in 1956, aided by the Guatemalan government.

This latter partnership is responsible for the restoration of Tikal. Your Guatemalan guides will tell you that the altars of Tikal were never overgrown or in disrepair, because they have been used continuously for nearly 3,000 years.

Your guides will explain that Tikal was a center where ideas as well as goods were traded. The guides will also explain something of how the Maya lived and worshipped.

They'll talk about the 20-year cycles, called katuns. It seems that buildings were built and added on to for a period of 20 years, only to be abandoned as a way to mark time, part of the ritual of moving on to the next katun.

The guides will also talk about the rituals of bloodletting. (Perhaps only the king had to pierce his genitals, perhaps other royals did as well). They'll talk about the ball games in which, it seems, the losers were sometimes put to death.

But if the culture seems raw and rugged in some ways, in other ways it was quite sophisticated. Proudly, the guides describe the precision of the astronomy. They find the Mayan calendar superior to the Roman calendar in that it doesn't need a leap year.

And there's more. In the Tikal national park guidebook, Thor Janson notes, "The foundations of the great Mayan temples were correctly engineered to be tangent to Earth, indicating that the architects were conscious of the planet's spherical surface curvature at a time when European authorities insisted the Earth must be flat."

Though the temples look like they are huge inside, they are not. The stones have been laid in concentrically smaller rectangles. Each temple is built over the burial tomb of a noble person. So while the imposing pyramids might appear to have something to do with government, you will discover that the governing of the city-state, as well as the ceremonies and the buying and selling, took place in the palaces and outside on the plazas.

At several spots around Tikal, you will see stelae, which are rock slabs, dense with carvings. Each stela is a historical marker covered with hieroglyphics about the reign of a particular ruler. Because of the stelae and the hieroglyphics decorating temples and palaces, scholars knew the Maya were literate. Yet for decades, no one could decipher their writings.

Various guides will tell you, sadly, of the destruction of an entire library of Mayan books. All but four books were burned by a Franciscan priest named Diego de Landa. De Landa, who lived from 1524 to 1579, had been sent from Spain to bring Christianity to the Yucatan.