With the backing of municipal permits and authorisation from the National Institute of Archaeology and History, Wal-Mart is building its new store on a 1.5-hectare plot of land which forms part of the nearly 500 hectares that are left of Tollan Teotihuacan, an indigenous name that means "Where Men Become Gods".

The store's neighbours are the pyramids of the Sun and the Moon, the numerous temples and the Avenue of the Dead in Teotihuacan, estimated to be more than 1,400 years old.

The construction of the store "is absurd, but in this country, anything can happen," said Lorenzo.

In response to the Civic Front's protests, the governmental National Council for Culture and the Arts promised that it would review the legal aspects of the project, about which it claims to have received no prior notice before construction began.

UNESCO (the United Nations Educational, Scientific and Cultural Organisation) also said it would investigate.

"We are prepared to take drastic measures, but sadly there are people living near the pyramids who support the store, because they say it represents progress," said Lorenzo.

In late July, around 50 members of the Civic Front, which is mainly made up of peasant farmers, teachers and a few owners of small local businesses, occupied the building site for three days, demanding that construction be brought to a halt.

The protest ended peacefully, but the construction work continued, and a few days later Wal-Mart called for trials of those who occupied "its property."

"The Teotihuacan community is divided, that's true, but those who believe in the defence of our history, culture and identity will fight to the very end to prevent a transnational corporation from stealing our history," said Trujillo.

The National Council for Culture and the Arts said it would examine the building permits, and would block completion of the new store if irregularities are found.

After the Civic Front filed complaints and the authorities investigated, the incomplete construction sites of two shopping centres were demolished in 1993 and 1997, not far from where the new Wal-Mart store is going in.

When it laid the foundations of its new store, Wal-Mart reported that a private archaeologist it hired found just a few isolated artifacts, like a ceramic container and an arrowhead.

But Trujillo said that could not possibly be true. "We are from this place, and we know that there is much more than that beneath the ground in this area," he argued.

Teotihuacan is a religious citadel built at the dawn of the Christian era. The city reached its peak of splendour between the years 450 and 600 AC, but by the year 700, the local residents had left the area for unknown reasons.

The name Teotihuacán came from the Aztecs, who discovered the abandoned buildings around the year 1300.

Impressed by what they had found, the Aztecs thought the pyramids had been built by giants with the help of the gods, according to historians.

The citadel originally covered about 3,500 hectares. But with the passage of time, settlements grew up around it, leaving unoccupied only the main ceremonial centres, where the pyramids are located, and a "buffer zone" where construction is limited.

But that zone, where Wal-Mart is building, has gradually shrunk.

Most of the area that was once Teotihuacan, a city that at its height had a population of 200,000, is now covered by houses and roads -- and, soon, a giant Wal-Mart hypermarket, if the Civic Front's efforts are unsuccessful.

Within the 3,500-hectare area occupied by the ancient inhabitants, towns have cropped up like San Juan Teotihuacan, Santa María Coatlán, San Martín de las Pirámides and San Sebastián Xolapan, which are already home to more than 500,000 people.