"Paul McCartney read our letter and said No!! to Chichen Itza. Thanks Paul — We love you," said a poster created by Mexico City archaeologists protesting the use of pyramids for rock concerts and New Age entertainment spectacles. (Annie-Marie O'Connor)

Mexicans are taught to revere their pre-Columbian roots. So some archaeologists are outraged by what they view as the government’s failure to safeguard the nation’s Mayan palaces and Aztec pyramids.

A recent decision by the government to erect a glass-and-steel facade on a portion of the historic Fort of Guadalupe in Puebla in time for the Sept. 15 Mexican independence celebrations was the last straw. The archaeologists have occupied Mexico’s prestigious National Museum of Anthropology, telling visitors that taking liberties with federally protected buildings was becoming commonplace.

The late-summer tourists who flock to the Chapultepec Park institution are greeted by banners, petitions and angry anthropologists with megaphones. A barefoot Mayan-speaking researcher in a white tunic blows into a conch shell to announce speeches in the lobby.

The occupying scientists have also declared: Admission is free.

Archaeologists are tweeting about “aggressions against patrimony” and using Facebook to decry tacky tourist development and New Age spectacles that they say will ruin the ruins.

Just when government officials were hoping to make money on the hype over Dec. 21 marking the end of the world, as predicted by the Mayan calendar, archaeologists are threatening to shut down the party even before it has begun.

“Our national monuments are being violated,” said Felipe Echenique March, head of the union that represents the National Institute of Anthropology and History (INAH), the government agency charged with protecting historic sites. “Public archaeological sites are deteriorating. We are resisting this destruction.”

Authorities were largely silent until last week, when the agency’s archaeological council said in a communique that it “categorically denied the claims of union groups pursuing political aims.”

Echenique said authorities called him into the attorney general’s office Thursday and accused him of depriving the National Museum of Anthropology of more than $400,000 in revenue since the protest began late last month. Spokesmen for the attorney general’s office said they were unaware of the conversation.

“We do have a political aim,” Echenique said. “We want enforcement of the federal laws that protect patrimony.”

In recent days, protest banners have spread to sites such as the former palace home of Spanish conqueror Hernan Cortes in Cuernavaca and a church in Nuevo Leon, aimed at what one bulletin called “the enemy in the house” — ineffectual leaders of the INAH.

Archaeologists have come from Michoacan to protest the ongoing construction of a museum on a pre-Columbian base at the complex of circular pyramids at Tzintzuntzan, or “place of the hummingbirds,” the capital of the Tarascan people until the Spanish conquest.

“They should not build this in an archeological zone. There might be important tombs below,” said Celia Gutierrez Ibarra, a 33-year state historian and author who stopped by to sign a petition calling for the protection of historic monuments.

“This is a very healthy protest,” she said. “You can’t make changes to historic sites to make them more tourist-friendly or let officials turn pyramids into Disneyland. This patrimony does not just belong to me, or to Mexicans, but to the whole world.”

Chihuahua historians came to protest the removal of a row of colonial buildings in Hidalgo del Parral by local authorities who thought a less cluttered plaza was better for tourism in an act of “misunderstood overnight modernity,” a furious preservationist told Proceso magazine.

INAH architect Carlos Huitz pointed to protest posters showing gothic-style ceilings that have been grafted onto traditional arched brick ceilings during the reconstruction of colonial convents in Oaxaca.

“Local authorities saw these someplace else and just decided to copy them,” Huitz said. “These don’t belong on these convents. They didn’t care.”

At a time when a debunked theory of ancient Mayan scripture announcing the end of the world in December is drawing droves of tourists to Mexico, Cancun is to host a “light, peace and world harmony” spectacle at the Mayan “Ruins of the King” palace complex during the fall equinox next month.

“The people who approved this are totally corrupt, shameless bandits,” Echenique said. “The 2012 movement is exploiting the ignorance of the people to earn millions of dollars. This has about as much to do with the Mayans as [Luciano] Pavarotti had to do with Chichen Itza.”

The protesters claim victories. Earlier this year, protest leaders sent letters to representatives of Paul McCartney, begging him not to hold a spring rock concert at the base of the Chichen Itza pyramid in the Yucatan, which has been the site of concerts by Placido Domingo, Pavarotti and Elton John.

The McCartney Chichen Itza concert never materialized, although he played in May at the capital’s Estadio Azteca and before 200,000 people at a free concert in the Zocalo. Authorities said McCartney had prior commitments.

“These are not profit centers,” scolds the protest movement’s Web site, under a photo of Chichen Itza and Teotihuacan, where workers drilled into the pyramid for a controversial but potentially lucrative light show that fizzled under pressure.

But alongside the state commitment to preserving Mexico’s past, there is pressure to earn revenue and a history of uneven local application of laws to protect its archaeological treasures, analyst Jorge Chabat said.

“They build a Wal-Mart at Teotihuacan and it creates a scandal, but in a few days, it blows over,” he said. “They use a pyramid for concerts, there is an outcry, and they say they won’t use patrimony this way. Then, they do it again.

“This is a debate that is always relevant.”