(AP) -- When neighbors in the hills east of Mexico City saw backhoes ripping up pre-Hispanic relics for a highway, they did something unexpected in a country where building projects often bulldoze through ruins: They launched protests to stop the digging and demanded an accounting of what is there.
Dozens of residents set up a protest camp and filed complaints with state and federal officials, demanding the highway be rerouted, hoping that studies of the site can help solve an age-old riddle about their town.
A story passed down for generations says Amecameca once stood on another site, and was abandoned after an eruption of the Popocatepetl volcano that looms over the town. Local residents suspect that the ruins, which are believed to date from 700 to 1,100 A.D. and are located on the outskirts of the present-day settlement, could help answer that question.
"This represents a possibility for the people to recover that part of Amecameca's history," said activist Rebeca Lopez Reyes, of the local preservationist group Guardians of the Volcanos. "We could find out what happened there, if it was evacuated or covered."
The idea is not far-fetched: Other settlements around Mexico City have been found half-covered in lava from volcanos that ring the valley, much as Italy's Vesuvius volcano once buried Pompeii.
The ruins detected so far in Amecameca are not particularly spectacular. Only about 120 square yards (meters) of the estimated 5-acre (2-hectare) site have been excavated, revealing stone and clay footings for houses that may have supported upper walls of wood or clay wattle.
But the very ordinariness may mean the site is unusually significant.
"What makes this important is that it is a residential area, not a ceremonial or religious site," said Felipe Echenique, a historian who serves as leader of the academic workers' union for the National Institute of Anthropology and History, or INAH, which is in charge of reviewing the site.
"In Mexico, we really have very little evidence of how the cities really were, or how people lived," said Echenique, who was not involved in the dig but is familiar with preliminary findings.
Towering pyramids in Mexico like Chichen Itza or temple complexes like Uxmal are well known, but the vast urban centers that supported those ceremonial sites have largely disappeared.
The housing compounds were apparently constructed by one of the still-unnamed cultures that populated the Valley of Mexico long before the Aztecs appeared in the area in 1325 and founded Tenochtitlan, the precursor to Mexico City.
Lopez Reyes said researchers called in by the INAH to investigate the site of the proposed roadway have found ceramic pots, bones and a stone serpent's head, suggesting that the god Quetzacoatl, "the Feathered Serpent," may have been worshipped there centuries before the Aztecs paid him homage.
The Institute has not released a formal report on what was found, saying researchers needed more time.
The few excavations of residential areas carried out so far in Mexico have yielded fascinating details.
In Teotihuacan, one of the biggest pre-Hispanic cities located northeast of Mexico City, some houses appear to have been illuminated by narrow doorways that opened onto central patios with shallow pools that acted as "water mirrors" to direct light inside the rooms. Techniques for building windows were apparently not yet known.
Investigators say similar discoveries could emerge from Amecameca.
"In what has been excavated so far ... there some strange settlement patterns that are emerging," said Echenique. For example, between one housing compound and another, researchers found an empty area that contained no relics - something that would be unusual in a densely populated area unless it represented a border between neighborhoods, a street, or contained some long-vanished wood structure.
Perhaps the most unusual thing is that local residents were the ones who noted the relics and called in the researchers.
"The inhabitants of Amecameca were more or less following the work on the roadway, and when they saw that there were a lot of relics coming up, they notified the Institute," Echenique said.
Progress has often trumped history in Mexico, where roads have regularly been pushed through ruins.
In Mexico City, the lava-buried remains of the ancient Cuicuilco culture, with its famed round pyramid, are crowded and partly covered by shopping malls, housing developments, a major freeway and even a college for archaeologists.
The Amecameca protesters have set up a camp to guard against construction work or looters and to explain the ruins to passers-by. They are asking the road be rerouted.
"The planned route wouldn't have to be changed that much," Lopez Reyes said.
Authorities have not yet commented on the demands, and the builders of the roadway, known as the Mexican Beltway, did not immediately respond to requests for comment. Nor did the Mexico State transportation department that is overseeing the project.
INAH spokesman Arturo Mendez said that "in almost every project of this type, there are going to be discoveries" of pre-Hispanic material." Thousands of years of settlement have left potentially interesting relics scattered across the region.
The Institute normally sends in a rescue project to excavate, recover any significant items, carefully rebury the site for possible future exploration, and then allow the construction to continue.
That is basically what happened in the 1960s to Maya ruins known as "Tortuguero" in the southern state of Tabasco. It was split in half and largely covered by highway construction.
The site happened to hold a stone monolith or stella known as Monument Six, which contains one of only a couple of known references in Mayan glyphs to the date 2012, which some believe marks the end of the Mayan Long Count calendar and a possible apocalypse.
The inscription has become so famous that the Tabasco state government now uses it on advertisements to promote tourism, even though the stone fragment itself sits in a museum in the nearby city of Villahermosa and little is left of the ceremonial site where it was excavated.
The people of Amecameca say they want to prevent that from happening to them.
Maria de los Angeles Eusebio, 55, a retired anthropologist, is one of the local residents who have camped out for the last week to prevent construction machinery from going through. Equipped with tents, coffee "and lots and lots of blankets," residents are staying day and night, through wind, rain and cold, to ensure the remains of their ancestors' city aren't destroyed.
"We don't want them to just bury this and run the highway over the top of it," said Eusebio. "We want them to return the artifacts, so we can display them in a museum for the community."
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