Holy Mole

Nobody knows who built the largest city in the ancient Americas, and the people who gave it its name did not know either.

Previously, in Brazil

Mexico was the third leg of a run that started at home in São Paulo, hosting extended family. Park walks, jungle hikes, rodízio dinners, and card games (like super intense). We celebrated the Fourth of July with a 'murica feast on our brand-new BBQ, then made the rounds of the city's monuments and churches. Rio came next: sunsets over Sugarloaf Mountain, dinners by the beach, and Christ the Redeemer, where many priests joined Sister-Sister in her devotion right there on the lookout. Then we flew north.

The Aztecs were tourists here too

Teotihuacán sits about 50 kilometers northeast of Mexico City, and I owe it an apology. I called it Aztec ruins. It is not. The city was razed by fire and abandoned in the 7th century, centuries before the Aztec Empire existed. At its peak it covered 36 square kilometers, with the Pyramids of the Sun and the Moon lined up along a single grand avenue.

When the Aztecs came across it, it was already a ruin, and an awe-inspiring one. They named it Teotihuacán, "the place where the gods were created," because they believed that is literally what had happened there. They named the main road the Avenue of the Dead, on the theory that the platforms along it were tombs. They were guessing. So, it turns out, was I.

What we do know is who did the building: a city of potters, craftspeople and, above all, glassworkers.

The green glass economy

Which brings me to the obsidian workshop.

Obsidian is volcanic glass, lava that cooled too fast to form crystals. It breaks into edges sharp enough that for most of Mesoamerican history it was the cutting tool, the blade and the spearpoint. Teotihuacán sat close to two of the best sources in central Mexico: gray obsidian from Otumba and a rare green-gold glass from the Sierra de las Navajas in what is now Hidalgo. Mexico's National Institute of Anthropology and History (INAH) has located more than 500 mine shafts in that range.

The INAH researchers think the work was split in two. Miners roughed out blanks at the deposit, then carried them back to finish in the city, because the carving is unforgiving and one bad strike ruins the stone. It made more sense to risk the mistakes at the mine than after hauling the rock home. Green obsidian traveled as far as the Maya city of Tikal in Guatemala.

So when you sit down at a workshop table near the pyramids today, you are not doing a cute craft activity. You are doing the local industry, roughly two thousand years late.

Holy Mole, and other religious experiences

Mexico City fed us relentlessly. Tacos in abundance. A vegan "Holy" Mole cooking class. Mexican fusion. A mezcal tasting, which comes with its own correction: all tequila is technically mezcal, but not the other way around. Mezcal can be made from many species of agave, and the hearts are traditionally roasted for days in underground pits lined with stone, which is where the smoke comes from. Tequila is made from blue agave and steamed in ovens. Certified mezcal is always 100% agave.

We paid a visit to the Basilica of Our Lady of Guadalupe, the most important Catholic pilgrimage site in Mexico. There are two basilicas on the plaza, and the reason is structural. The old one, finished in 1709, was being pulled apart by earthquakes and subsidence. The new round basilica opened in 1976, and because it has no interior pillars, the image of the Virgin can be seen from almost anywhere inside.

Out in the city, we caught a march through the Zócalo, complete with mariachis, and balanced it with quieter park walks. And, most importantly, family hugs.

The hole in the Yucatán

Then I headed to the Yucatán, where I marveled at the Maya ruins of Chichén Itzá and took jumps into a cenote with newfound friends.

Here is the thing about cenotes. The Yucatán is a vast slab of limestone, and rainwater does not so much run across it as through it, dissolving caves underground. A cenote is where the roof of one of those caves has collapsed and opened a window onto the groundwater. For the Maya, that was the water supply. Chichén Itzá's name is usually translated as "at the mouth of the well of the Itza."

And here is the part that got me. In the northwest of the peninsula, the cenotes are not scattered randomly. They cluster in an arc about 180 kilometers across, the Ring of Cenotes, tracing the rim of the Chicxulub crater, buried under the limestone and left by the asteroid impact at the end of the age of the dinosaurs. Geologists think the slump faults at the crater's edge made the rock more permeable there, so the caves formed and collapsed along the old rim. The Yucatán government has registered more than 2,200 cenotes and estimates that is only about 70% of them.

So the swimming holes that kept Maya cities alive, and the one I was jumping into, are in part the long tail of a catastrophe. Water found the cracks the asteroid left.

Pink, and not for the reason you think

The Yucatán had one more correction for me, and it came in pink. I ended up on top of a hill of salt, next to a lagoon the color you would assume was a filter. It is not a filter. These are salt-evaporation ponds: seawater is let in and left to the sun, and as the water evaporates, the brine gets saltier than almost anything can survive.

Almost. Two kinds of specialist move in. One is an alga, Dunaliella salina, which stockpiles beta-carotene (the carrot pigment) to shield itself from the sun. The other is a group of salt-loving microbes called halophilic archaea, which carry a red pigment of their own. You would think the alga, with all that carotene, is doing the coloring. A study of saltern ponds found the opposite: the alga holds most of the pigment, but it is packed into tiny globules inside its cells, so it barely shows. The color of the water matches the archaea.

The alga has most of the paint. The archaea do the painting.

If you go

• Teotihuacán is a day trip from Mexico City. It is run by INAH; check hours and fees on the official site before you go, and get there early. The site is large and very exposed.
• Obsidian. The green-gold glass sold near the pyramids comes from the Sierra de las Navajas source, the only green obsidian in Mesoamerica.
• Mezcal. Look for certification on the label. Certified mezcal is 100% agave; the species and the roasting are where the flavor differences come from.
• Basilica of Guadalupe. December 12 is the feast day and draws millions of pilgrims. Wonderful if that is what you came for, a lot if it is not.
• Chichén Itzá is in Yucatán state, not near Mexico City, so plan it as its own leg. At the spring and autumn equinoxes the setting sun throws a serpent of light and shadow down the north stairway of El Castillo, clouds permitting, and the crowds come for it.
• Cenotes. Rules on jumping vary from cenote to cenote. Ask before you leap.
• The pink lagoons are working salt ponds, not a nature park. Go when the sun is high; the color depends on the light.

Corrected by Mexico

Mexico corrected me at every stop. The Aztecs were not the builders, tequila is a kind of mezcal, the church is sinking, the swimming hole traces a crater, and the pink is not the algae. Every place we went had already been someone else's ancient discovery. That is what made it feel so alive: the whole country is built on people standing in front of something older than them and deciding it was holy.