Tourists who visit only its touted coast cities--or even the country's mountain-ringed capital--are missing the best part of Mexico, I think.

Travelers who are more in tune with geography and history than with sunbathing and entertainment will go south in our south-of-the-border neighbor for some really intriguing travel time.Southern Mexico boasts areas of astounding natural beauty - of mountainous jungle and lush agricultural regions - places such as Agua Azul, where a mountain stream descends in a series of terraced waterfalls that culminate in a broad pool worthy of the name, which translates into Blue Water.

But the area's greatest attraction, from the perspective of this traveler, is the lure of archaeological sites rich in the histories of long-gone Indian civilizations.

Such sites sometimes pop into view, leaving one with a fractured sense of time. After a ride through jungled mountains on narrow, winding roads, ancient stone buildings suddenly spring from the jungle floor in a movie-set unreality that throws viewers into a time warp.

The pre-Columbian history of Mesoamerica (primarily southern Mexico, Guatemala and Honduras) is fascinating. Civilizations that paralleled - and in some aspects rivaled in complexity and advancement - those of Egypt, Europe, Mesopotamia and the Orient, rose and fell and were consumed by relentless jungle growth. Ruins from these civilizations are now being unearthed in various locations throughout Mesoamerica and are slowly yielding the secrets of their fascinating pasts.

Maya, Olmec, Toltec and other groups thrived in the beneficent climate. They fought their wars, sculpted culturally significant figures, created calendars of unprecedented accuracy, strutted their piece in history, wrote their stories (still largely undeciphered) and fell into decay.

We traveled by bus from Guatemala into Mexico, crossing the border near Tapachula, where we spent a night anticipating a visit to Izapa. The site is a huge outdoor temple complex, a remnant of a large settlement that antedated the Christian era.

Izapa is of particular interest to scholars of The Church of Jesus Christ of Latter-day Saints as the location of the "Tree of Life" stela. The carved stone, dubbed No. 5, is one of many that ring a football-field-sized plaza. Each pillar is astronomically significant and some still are fronted by altars.

Stela 5 contains figures that appear to LDS scholars to support both Book of Mormon and Bible history, and the stone's symbolism has been studied, dissected and replicated in many church publications, although there is no official church position on the authenticity of the assumptions.

The unpracticed eye might slide right over Izapa without stopping. From the road, the site appears to consist only of stands of banana and cacao trees in an area of many such stands. But as our guide, Richard Jones of World Wide Expeditions, explained details, the historic nature of the site began to unfold.

The gentle mounds over which we walked to the visible archaeological remains of the site consist of successive layers of soil, dropped leaves and fronds. This accumulation of more than two millenia actually is believed to cover more than 80 pyramid-like structures. The site was once a thriving trade center in which ancient Mesoamerican cultures crossed paths.

Mexican farmers who work the land today occasionally uncover stelae that have been hidden for thousands of years. The carvings depict the religious and historical lives of a people that were intermediary between the dominance of the Olmec and Mayan cultures.

A visit to Izapa provides not only a glimpse into a long-gone civilization, but an interesting look at the modern families who now occupy the site. The government-appointed care-taker of the site has five children - a propitious number, he told us, that brings the family total to a lucky seven. One daughter fried tortillas on a grill in the yard while her father provided lukewarm soda pop for our tour group, wet and welcome after our trek through the hot, humid environs to see various stelae.

Further north and east is Palenque, a jewel among Mesoamerica's archaeological sites.

The complex of gray-white buildings blossoms out of the green jungle growth in a refreshing, other-worldly contrast. Ubiquitous green still obscures the exact boundaries of the site, but it is known to extend three and a half miles west and two miles east of the chief ceremonial buildings.

The Mexican government began in 1923 to unearth the mounds that held the secrets of a people who reached their apex in the period 600 to 900 A.D.

First to be unearthed was the imposing Great Palace, a labyrinthine collection of small rooms, corridors and central living areas surrounding a tower, the only one from the Classical era known to exist. A small stream dissecting the vale in which Palenque is located was diverted through an aqueduct to serve the needs of the royal family and entourage.

The Temple of Inscriptions provided one of our trip's great adventures - a taxing climb first up the steep back side of the pyramid (preferable, at that, to the narrow, steep stairs that give access from the front) then back down into its bowels where the burial place of Pakal the Great lay undisturbed until 1952. The discovery of the entrance to the tomb, located beneath huge stone slabs that had appeared nothing more than floor, is counted one of the great archaeological highlights of Mayan study.

Spending a few hours absorbing the atmosphere of Palenque serves mostly to whet the appetite for a return when time is not a factor. In a short visit, the magnitude of its history and its legacy can only dimly be perceived. It's at the top of my list of Places to Explore More Thoroughly.

Palenque is within easy reach of Villahermosa, an attractive mid-sized city with tourist amenities comparable to those in Mexico City. The city boasts a fascinating outdoor musuem that features an outstanding collection of archaeological items.

A stroll along its shaded walkways brings a new treat at every turning. Huge, football-helmeted Olmec heads, squat seated figures with near-Oriental features, an intricately carved stela that depicts the meeting of a man with amazingly Mideastern features with one more Indian in nature are only a few of the intriguing items in the collection. A stylistic serpent carving that convinced at least one author that outer space aliens had visited Mesoamerica is worth a prolonged period of contemplation.

At LaVenta, still farther north, we climbed a 100-foot high manmade pyramid believed to be the oldest of its kind. The area was a center of Olmec culture before the advent of Christ, and many of the gigantic heads equated with that people were found in the region.

Market day in San Cristobal de las Casas provides another tourist dimension. The city's streets swarm with vendors, many of them children, in the colorful blue-dominated local clothing. They vie vociferously for the tourist's pesos, offering hand-woven goods, very simple dolls in matching native attire, food items and the routine doodads of the tourist trade.

One enterprising young fellow toting a shoe shine kit persistently coaxed for customers, ignoring the fact that most of us wore standard U.S. canvas shoes.

As in most Mexican towns, the Catholic cathedral commands an imposing central spot adjacent to the plaza. The cathedral in San Cristobal is a particularly attractive example of its genre and a vivid contrast to the evident poverty of many of the city's residents.

The town is near the Bonampak ruins, where amazingly intact ancient murals were discovered. Again, time didn't allow for a visit. Add Bonampak to my "futures" list.

Other highlights of our trek through southern Mexico included:

- Pineapple from a roadside stand surrounded by fields bristling with ripe fruit had a taste to be remembered - the essence of sunshine in dripping juice, a treat that can't be duplicated from American markets.

- The Coatzacoalcos River, which empties into Campeche Bay and is large enough to accommodate ocean-going vessels. On its shores, Cortez made his first encampment in 1519 as he returned to Mexico to begin a conquest that would forever change the course of western hemisphere history from Mexico southward.

- A brief stop at Chiapa de Corzo, where Brigham Young University excavated and rebuilt a pyramid that was threatened by a road construction project. The Mexican government acceded to the university's requests, building the road on each side of the site to allow its reconstruction. An ox cart loaded with wood and topped by a curious youngster ambled by as we explored, a reminder that much of Mexico still lives in the past, from our perspective.

- Howler monkeys in the Juxtla Guiterrez Zoo, whose deafening screams precluded much conversation about the coati mundis, wild turkeys, jaguars and other animals that share their environs.

- Lake Catemaco, where the sunset painted a golden swatch from mountains to shore, silhouetting palm trees and creating a colorful stage for the dip-and-dance of hundreds of birds.

It was a fitting spot to say goodbye to southern Mexico as we headed for Mexico City and the end of a fascinating trip.