While nearby Monte Albán impresses by its size and commanding location, Mitla impresses by its form and geometric detail. At Mitla, Carefully cut and laid stones create patterns, called grecas. Some of the original red paint remains, highlighting the natural color of the stones.

There's something fascinating about repeating geometric patterns. Seeing a surface covered by an interlocking set of tiles must provoke neurons deep in the brain to fire in biological harmony. This deep-brain consonance is strongly felt at Mitla. It may, in fact be what gives this Zapotec site its mystical nature. When you are among the buildings, it feels appropriate to talk in hushed tones; an occasional visitor will sit and meditate in one of the now roofless inner chambers.

Like no other Mesoamerican site, Mitla presents visitors with buildings and walls covered by detailed, repeating geometric patterns. Made with thousands of stones laid one atop the other, some protruding, some recessed, the patterns, perhaps because of similarity to Greek designs, are often called grecas.

The hall of the columns, once with a roof was the temple antechamber where worshipers could enter. To the left is the inner chamber where the priests performed their sacred rites.

The harmony of the architecture comes from low, well proportioned rectangular buildings surrounding broad open plazas. While nearby Monte Albán impresses by its size and commanding location, Mitla impresses by its form and geometric detail. Some see feathered serpents in the grecas, but surely their elegant repeating geometry alone would have been enough to inspire the appropriate amount of awe in visitors to the site--especially when set off by the deep red colors that remain as traces on a few of the walls. The designs continue in use today in the rugs of many of the Zapotec weavers living nearby.

The harmony of Mitla's architecture comes from low, well proportioned rectangular buildings surrounding broad open plazas.

Mitla is at the upper end of the Tlacolula Valley, one of the three valleys that come together to form a three-pointed star that is the Valley of Oaxaca. Monte Albán, as befits its role as the major power center is at the intersection point. Mitla, as befits its more religious nature is located at a remote, less central location. Visiting Mitla requires a pilgrimage.

Surfaces of some of the buildings are almost covered with panels of grecas, each a different design.

Archaeologists use the Oaxaca Valley as a laboratory for the study of emerging civilizations. The dry climate and the small amount of erosion have preserved sites that date from 10,000 years ago. The concentration of good land and the difficult-to-cross mountains resulted in a social evolution that started with a handful of people living by moving from place to place in search of edible plants and animals. This evolution went through many stages and culminated in a state, governed by kings and nobles with craftspeople, farmers, hunters, warriors and a highly developed religious elite. This state, the Zapotecs, fought, engaged in trade, sent diplomats across Mexico and built cities, religious centers and monuments.

By the time that Cortés was named Marquis of the Valley of Oaxaca, the Zapotec State had over 500,000 people. Their architecture made use of adobe, stone masonry, lime and plaster. They had developed a system of writing, and used a 260-day ritual calendar as well as a 365-day solar calendar. They had domesticated maize, beans, squash and peppers and had developed irrigation systems that used wells, dams, canals and terraces to grow food for a highly urban population.

Nobles buried at Mitla were undoubtedly destined to become cloud people who could intercede with Lightning on behalf of the population.

Church of San Pablo, built by the Spanish on top of the site, using stones from the temples. Grecas remain in the wall.

During this evolution, Mitla grew from a fortified village on the outer edge of the Valley to be the main religious center and was still active when the Spanish arrived. The high priest, or Uija-tào resided at Mitla. Arriving Spaniards likened him to the catholic pope. As befits such an import religious figure, the Uija-tào lived in a "temple", called a yohopàe, or "house of the vital force". This temple at Mitla faces a broad courtyard. You enter through a door flanked by two massive columns, and as is characteristic of Zapotec temples, enter the antechamber where worshipers would have come. The antechamber at Mitla once had a roof, supported by six columns. Only the columns and walls remain. Behind the antechamber is the inner chamber where the priests burned incense, sacrificed animals, sacrificed humans and performed other rites. Behind the inner chamber is the apartment of the priest. Walls everywhere are covered by grecas.

The Zapotec religion worshiped two main gods, Sky and Earth. The Zapotecs made a major distinction between objects containing "life" and objects that did not. The forms of their gods that contained "life" were Lightning and Earthquake. Lightning was the most powerful. Dead ancestors from the ruling class could join Lightning as a cloud person or ben zaa. Ben zaa were venerated and worshiped in what some describe as similar to saints in western religions.

The entrance to the hall of the columns is two massive supports that create three doors.

The name Mitla comes from the nahuatl wordmixclánfor "place of the dead". Burials at Mitla were reserved for special members of the upper class. They were undoubtedly destined to become cloud people who could intercede with Lightning on behalf of the population.

Alfonso Caso, the archaeologist who excavated Monte Albán also did work at Mitla. In a 1933 National Geographic, he wrote "I found on a stone, a wreath of flowers ... which are the indians in their burial ceremonies and the remnants of a wax candle which some pious had lighted to appeal to the gods of Mictlán ... for the eternal rest of his relatives."

Some of the tombs have been discovered. So far all are empty. Walking down the narrow steps and into one, you see that its shape is like a cross. It's likely that the builders who took the care and time to cut, polish and arrange hundreds of thousands of stones into complex geometric patterns were acutely aware of the symbolism connecting a four part tomb with the four parts of the universe fundamental to Zapotec belief.

The grecas draw your eye, they fascinate, they change with the light.

Greca detail.

Some have speculated that the grecas convey an abstract version of Quetzalcoatl, the feathered serpent common to many mesoamerican religions. The Zapotecs, early on, did develop stylized symbols for Lightning, as a snake with flames above its eyes, and Earth, as a mask with a cleft head, but it's hard to see either of these symbols in the grecas, let alone a feathered serpent.

If a Zapotec temple was a "house of the vital force", then the grecas are one way of bringing the temple to life. They draw your eye, they fascinate, they change with the light. By day, the shadows change as the sun moves across them. Lit by torches, they would be alive, their geometry casting shadows that responded to every movement of the flames. But, their geometry alone is enough. They fascinate today, as patterns that make the stones come alive. They probably fascinated as much or more when Mitla was alive with priests, pilgrims, nobles and other members of the Zapotec State.