The trips have become more popular as roads and air links improve, making once-remote ruins easier to get to, organizers say. But they are pricey, with some trips stretching for 21 days and costing more than $4,200, not including airfare.

Central America and southern Mexico are the most important destinations for such tours because of the advanced cities and writing systems that existed there from 600 B.C. to A.D. 400, the main period covered by the Book of Mormon, Allen said.

But the tour groups differ over the exact sites. L.D.S. Guided Tours says the ancient city of Bountiful, where Jesus appeared to the Nephites, may be the Mayan city of Dzibanche in southern Mexico. Liahona Tours says it could be El Mirador, 90 miles away in Guatemala.

Other companies focus on Tikal, 40 miles to the southeast of El Mirador or on another site 200 miles west in Mexico's Tabasco state.

Most Latin American archaeologists say there are no connections between the Mayas, who lived in that area, and the Hebrew tribes of the Middle East.

"These are completely different cultures, and they developed in a different space and time," said Jose Huchim, an archaeologist and Mayan expert with Mexico's National Institute of Anthropology and History.

Even Mormon archaeologists say it will take decades of digging for artifacts before the Book of Mormon can be proved or disproved.

"I just see the tours as entertaining, and I try not to get upset that people are wasting their money doing foolish things," said John Clark, director of the New World Archaeological Foundation at Brigham Young University, which is owned by the church.

But the uncertainty didn't damper the spirits of the 18 travelers at Teotihuacan, the first stop on an 11-day Liahona Tours trip.

They nodded knowingly and chimed in with scripture references as archaeologist Kim Goldsmith, also a Mormon, described the use of cement and the way Teotihuacan's builders cleared the forest to make way for the city.

Archaeologists know little about the people who built Teotihuacan, not even the city's original name or what language was spoken there. The city reached its zenith between A.D. 250 and 600.

The city's builders may have been related to the Jaredites, whom Mormons believe came to the New World at the time of the biblical Tower of Babel, said Mont Woolley, the tour director.

But whether the archaeological evidence backs up the Book of Mormon is irrelevant, said tour participant Dawn Frenetti, 28, of Milpitas, Calif. Just seeing such sites is inspiring, she said.

"It definitely helps me stay interested in learning more about the Book of Mormon," she said. "But, as far as confirming my faith, my faith has always been there."<