CHOLULA, Mexico (AP) -- A lot has changed since this town was founded on a flat plain in the valley of Mexico.But no wonder -- that founding was 1,800 years ago. Cholula's residents have learned over the years how to blend their ancient history with their modern lives to create a community that is deeply religious yet modern -- and often very noisy with fireworks, church bells and the music of religious processions.Cholula, in central Mexico, is said to be the oldest continuously occupied town in all of North America. Anthropologists and town fathers say the town was officially founded in the year 620 A.D. And they say people have been living there even longer -- possibly since around the year 200 A.D.The ancient town has lots to offer visitors. Just a dozen miles from Puebla, Mexico's fourth-largest city, Cholula has several dozen elaborately decorated churches; a huge pyramid with a church on top and tunnels throughout; a yearly symphony of church bells; a religious fair that brings in an enormous market of arts and crafts; and, on a clear day, the sight of three volcanoes, one of which regularly belches smoke.The churches are a spectacular attraction. Local lore has it that Spanish conquistador Hernando Cortes ordered 365 Christian churches to be built when he arrived in Cholula around 1500 -- a church for every day of the year, as a means of promoting Catholicism. Only about 175 churches ended up being built in Cholula and neighboring villages, said Timothy James Knab, an anthropology professor at the University de las Americas in nearby Puebla who teaches a class about Cholula. But almost all the churches use fireworks to mark religious festivals, and almost all have multiple bells, so the sound of pealing bells and the sight of powerful pyrotechnics is a regular feature of life in town.The bed-shaking fireworks can be a surprise to visitors."They do have a constant need for explosions," said P.J. Ryan, 70, of Wheaton, Maryland, who spent three months in Cholula last winter. "Usually (when there are fireworks) there's an audience, but around here that doesn't seem to matter."Religious centerThen there is the pyramid, Tepanapa. Now mostly covered by earth and plants, the huge adobe structure looks at first like a pyramid-shaped hill rising out of the flat lands near the center of town. The pyramid was built by the Cholulteca people during the centuries leading up to 850 A.D., and features a large church on top, rebuilt several times over the last 400 years, that is still in active use. Visitors who are reasonably fit can climb the long, wide, winding stairs to the church and enjoy the views from the stone plaza on top of the pyramid -- cultivated fields stretching out in one direction and the city of Puebla in the other.For many years, Tepanapa was thought to be the largest pyramid in the world, with a length of 820 feet on each side and a height of 216 feet. It covers 10 hectares. It's no longer thought to be the largest -- but it does have the largest base of any pyramid in the world, said Knab. Visitors can tour the remains of several buildings inside by walking down a long, cool, narrow corridor within.Cholula is known as an important religious center, and its churches are generously decorated and scrupulously maintained. Domes and other interior walls are covered with statues of saints, children, fruit, flowers, birds and much more in plaster, wood, gold and paint, and many of the churches feature the colorful Talavera tiles that are a famous product of Puebla.The religious art and celebration doesn't stay inside the churches. Cholula has more religious festivals every year -- about 400 -- than any other town in Mexico, said Knab. The town is distinct because its social system, based on separate neighborhoods, is still functioning strongly, and each neighborhood, or barrio, still celebrates its own saints day with one or as many as 20 festivals featuring food, music, religious processions and of course fireworks. On important holidays such as Good Friday, the streets in the center of town are closed down and carpeted with flowers for the parades."Normally most towns will celebrate nothing more than their patron saint's day," Knab said. "Processions are almost constant here." A local band waits in front of San Diego church during a religious festival in Cholula.In November, Cholula holds a concert of its church bells, when all the bells of the barrios ring in sequence. The lights are turned off in the center of town, and townspeople carry candles as they meet in the Zocalo, or main plaza, to listen to the music.September is the time of Cholula's large fair celebrating the Virgin of the Remedies, the statue of the virgin now housed in the church on top of the pyramid. The statue itself, an 8-inch-tall figure left behind by a Spanish soldier in the 16th century, is taken down from the pyramid in September to begin a cycle of visits to Cholula neighborhoods. The Virgin of the Remedies is believed to be one of the most miraculous in Mexican culture, and the fair is a mammoth commercial event that attracts both buyers and sellers from other Mexican states with local crafts and products as well as plastics.During the fair, "all the streets in the Zocalo are filled with itinerant merchants," said Robert Shadow, an anthropology professor who has lived in the area for 20 years. "It's a very Mexican tradition, the fusion of commerce and religion."Cholula is a religious center, but the town has plenty of secular attractions as well, starting with the Zocalo, a large shady park that is surrounded by restaurants and stores. Shops selling local handcrafts including the Talavera pottery line many of the streets leading to the Zocalo, and the crafts -- local or from elsewhere in Mexico -- are affordably priced. A local culinary specialty, chilis en nogada, is made with green chilis, red pomegranate and white walnut sauce, reflecting the colors of the Mexican flag.The old city shows its ancient roots with narrow, cobbled streets and several huge stone plazas; walking is easy in town, and shade is plentiful. Jacaranda trees in flower provide splashes of color against the white stucco walls and the wrought iron of the traditional Mexican buildings. The town is set up for visitors, with many good hotels located downtown. Most of the tourists who visit Cholula are Mexican; the town is not on the regular route of Americans and Canadians. But it's well worth a side trip."I love Cholula; it feels different from any other city in Mexico," said Knab. "Everybody is still involved in their Saints days, their fiestas; this is the social glue that has held Cholula together for 2,000 years, and it still exists here."Copyright 2005 The Associated Press. 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