Through the window of the Ormeno bus, water somewhere between the color of lapis lazuli and blue hyacinths stretched as far as I could see, with a sweep of mountains in the background. Later, during a walk along the shore, I watched as women in shawls and straw bonnets fished from hand-thatched canoes. That evening, I dug deep into a feast of fresh lake trout and grilled alpaca steak at a waterfront restaurant in the Peruvian city of Puno. My first day in the Lake Titicaca basin was almost complete.

But I had traveled across two continents for more than just scenery and a taste of local cuisine. When the mighty Incas staked a stronghold in this corner of South America in the mid-1400s, they declared it the most sacred place in their empire. The waters had given rise to no less than the creator god Viracocha, by their account. Manco Capac and Mama Ocllo, the mythical founders of the Incan empire, were also said to have risen from the lake. Did that sacred spirit linger here? I had come to find out

It was not a journey for the weak-spirited. After an overnight flight from Washington to Lima, my companion Eddy and I took an hour-long flight to Arequipa in southern Peru, then a four-hour motorcoach ride to Puno, at the northern end of the lake. A flight into the Bolivian capital of La Paz, 45 miles from the lake, would have made for a less complicated trip. But strikes in Bolivia had closed the airport when we were making plans for our sojourn.

Many visitors devote only a couple of days to the lake, then move on to Machu Picchu or other sights in the Andes. Our five-day stay was just enough time to begin to grasp the history and depth of the place. And the climate in January -- sunny days peaking in the low 70s and crisp nights -- could not have been more pleasant.

Tititica owes its striking allure to geography. Straddling the borders of Peru and Bolivia, at more than two miles above sea level and 120 miles long by 50 miles wide, it is by far the highest large lake in the world. The surrounding Andes add to the grand vistas.

But it's the bold colors, remindful of the strokes Matisse splashed across his canvases, that make this scene one of the wonders of South America. Enhanced by the unremitting Andean sun, the lake's waters were starker than fresh blueberries, the wildflowers along the shore redder than blood. And the reeds shooting up from the water were greener than a field of shamrocks.

Puno, where we stopped the first night, did not live up to these exalted standards. This city of nearly a million people is a hodgepodge of concrete structures sprawling along the lake's edge. Even Jiron Lima, the main shopping street, was little more than an unsightly stretch of storefronts and cafes.

Advised that the town of Copacabana in Bolivia offered a more appropriate entree to the grandeur of Titicaca, we hopped a minibus for the two-hour trip there.

What a difference. With a population of 4,300, Copacabana is a neat enclave of low-rise buildings with red-tile roofs spreading from the edge of the water and up the side of a mountain. Along the lakefront boardwalk, strollers and vendors selling snacks and crafts make for a festive mood. At Snack 6 de Agosto, a popular local restaurant, we savored a lunch of grilled lake trout, roasted potatoes and fresh-squeezed orange juice -- standard fare in these parts.

Later, we visited the town's biggest attraction, the Copacabana cathedral. Built by Spanish missionaries in the post-Inca era of the late 1500s and early 1600s, it is an impressive Moorish-influenced structure with whitewashed stone walls and domes decorated with deep blue tiles. Inside, worshipers were gathering for midday Mass.

Around the corner is a chapel dedicated to the Virgen de la Copacabana, a major pilgrimage destination for Bolivian Catholics. Her portrait is visible through a vaulted door, encased in glass. She's dressed in a flowing robe, and her slight brown face seemed to stare directly at me.

Back in the sun, as I sat under towering palms in the Plaza 2 de Febrero, my desire to explore the spiritual depths of this region was stronger than ever. And so early the next morning, we climbed aboard the Titicaca, a rickety boat crowded with tourists, bound for Isla del Sol (Island of the Sun). At 13 by 5 miles, and with several thousand inhabitants, it is the largest and most populous island in the lake. A religious shrine for local tribes as long ago as 500 A.D., it was transformed by the Incas into a major pilgrimage destination in the 15th century.

Bolivians still revere it as the most important and most spiritual of the 40 or so islands scattered across the lake. As our boat approached, I chatted in Spanish with a Bolivian woman dressed in the traditional costume of straw hat and layered skirts. She and her husband and son had traveled from the opposite end of Bolivia for this outing. "All of my life I have wanted to come here," she said. "Now I feel the mood rising."

After landing at Challapampa, one of the small port towns along the coast of Isla del Sol, I could see what she meant. We hiked a coastal stone path, passing corn and grazing goats. Along the way, children dressed in brightly colored clothes peered from behind trees and boulders, their round brown eyes a mix of bashfulness and curiosity. After 15 minutes, we reached the remains of an Incan village, centered on a large stone block and a collapsed building.

Twenty minutes later, we arrived at our goal: the Sanctuario, a site of worship for the Incas. Bernardino Ticona, our guide, led us through temples tribal priests once used, stopping at a flat rock marked by two indentions shaped like animal footprints. This was where the Incans brought animals, birds, feathers and sometimes humans to sacrifice, Ticona explained.

Off to one side was a large stone that nature roughly shaped like a wildcat. In Quechua, the language favored by Incas, it was known as Titikala, the place of the puma. The lake was given the same name. Six centuries later, it has stuck.

And so, apparently, has its spiritual status. "Of course, we still believe in the powers of this site," Ticona said. "When we want to reach spirits from above, we come here."

After a trip back to Peru and an overnight in Puno, we made one last excursion -- to the famous floating islands of the Uros and the island of Taquile. In the blue light of early morning, we climbed aboard the Villa del Lago, a small wooden schooner, and were joined by a motley crowd of travelers, including a gaggle of Australian schoolgirls, two German women and a handful of Americans. Our guide was Angel, a 32-year-old Peruvian with indigenous roots.

Forty-five breezy minutes later we were stepping onto Chumi, one of a cluster of islands made of tortora reed near the northern edge of the lake. Ever since the time of the Incas, the indigenous Uros tribes have made the islands by hand, piling stacks of dried reed atop one another. When the lower layers dry out, new ones are added. Several huts made from the same reed were scattered about the island.

In the 1400s, the Uros made their homes on these floating outposts to escape the conquering Incas. Since the late 1960s, however, the islands have become less places of residence and more tourist attraction. By the time we arrived, a group of tribeswomen had already set up a mini-market of tiny canoes made of tortora, utensils carved of wood and other crafts. Men hovered at the edge of the island, offering boat rides in tortora canoes.

For me, the spectacle of handmade islands aloft on water was a rare, worthwhile stop. Others in the group were less impressed. Charles Koontz, an Ohio engineer who was touring the Andes with his wife, Julie, grimaced when I asked his impression. "This was a Disney version of indigenous culture," he said.

When we reached Taquile three hours later, all was forgiven. Three miles long and a half-mile wide, this is one of the largest and most intriguing of the enclaves scattered across the lake. First populated 10,000 years ago by the Tiahuanaco tribe, it was overtaken by Incas in the 15th century and later by Spanish colonists. Most of its 3,000 residents trace their roots to the original tribe.

As I climbed the 533 stone steps to a plateau and continued along a stone path, I noticed earmarks of different cultures. Along a hillside were the familiar terraces Incas used for growing crops. Atop a stone gate was a cross, the unmistakable sign of the missionaries' influence.

Inside the spacious central plaza, the scene seemed strangely untouched by the passage of centuries. A few men in wool stocking caps wandered about, knitting as they walked. Women dressed in layered skirts and black shawls squatted in the corners, spinning yarn. Workmen wearing sandals mended the facade of a stone building.

After our lunch of trout and rice, Angel explained that the locals go to great lengths to maintain the customs of the past. A few years ago, after visiting mainland Peru, a group of local youths asked permission to wear jeans and T-shirts. The island council rejected their request, by Angel's account. Through the centuries, married men have been required to wear stocking caps of red, while bachelors wear red and white.

Yanaparqui, a form of labor barter in which couples alternately work on one another's farms, has also continued since the pre-Christian era. The communal market, in which the profits of goods sold are divided among workers, is another longtime tradition. "Life here is about the same as it always was," Angel explained.

As the Villa del Lago made its way back to the mainland, I took a long look across the lake to the dazzling Cordillera Real range of Bolivia in the distance. Off in the horizon, the sun was beginning to disappear. My trip was coming to an end, and that was fine, too. I knew that the glory the Incas found in this region would continue forever.

Mystical Lake Titicaca straddles the border between Bolivia and Peru. Above, the sacred ruins on Isla del Sol; left, a local in tribal attire.Bolivia's Isla del Sol, on Lake Titicaca, is dotted with sacred Inca ruins.