The single carriage train runs along a narrow track deeper and deeper into the Andes, just feet away from the Urubamba River that roars down the deep valley. The sides of the mountains rise ever higher and steeper on either side, while the hypnotic Indian flute music piped over the train's PA system adds an eerie atmosphere of timeless mystery.

Machu Picchu: One of the true wonders of the world

Half a millennium ago, this was one of the routes Inca Indians took to reach their mountain fastness of Machu Picchu, named thus in modern times for the mountain in whose cradle it lies. No one knows what the Incas called it. The tourist route of today is probably not much different from that the Incas used when traveling from their capital city, Cuzco.

It is to Cuzco that one flies from Lima, an hour in the air that takes you centuries back in time from the modern world to the Inca era, when Cuzco was the center of the largest empire ever to exist in the Americas. The flight also takes you from sea level to 11,000 feet.

The hour and a half drive from Cuzco to Ollantambo, where you can pick up the single-carriage train to Machu Picchu, takes you across spectacular highlands, over 10,000 feet above sea level, where the Indians continue to till the soil as they have for centuries.

(Alternatively, take the Back Packers Express from Cuzco all the way to Machu Picchu, a three-hour ride. Both trains are operated by the London-based Orient Express company.)

The Urubamba River passes near Cuzco through what the Incas called the sacred valley, down past Machu Picchu and on to join the Ucayali River, one of two forming the Amazon (which is Peruvian before becoming Brazilian).

The Urubamna rivers winds beneath Machu Picchu

By the time you arrive at the train station for Machu Picchu, in the ramshackle village of Aguas Calientes, home to 950 families who make a living from the tourist trade, you have left farmland and Alpine-like slopes and entered the upper rain forests, or cloud forests, of the Amazon basin.

If you stay at the Machu Picchu Pueblo Hotel, barely visible amidst the trees and shrubs near the station, an all-local staff of 120 will take care of you well in an environment designed to put you in touch with the wonders of nature.

No, the floors are not pounded dirt, a la Inca, but all the buildings and furnishings have been made, with skill, by locals using local materials (except the phones, lights and plumbing fixtures!).

The hotel grounds boast what, "in all probability is the world's largest orchid species collection (some 380 species and counting) set in a natural environment in a private facility," according to the American Orchid Society.

There are also 14 species of hummingbird, the same number as found in all of North America. Oh yes, and a couple of Andean Spectacled Bears.

From the village a fleet of 20 buses ferries tourists across the Urubamba and up a winding road to Machu Picchu, which you enter for a $20 fee.

Undoubtedly one of the truly great archeological sites of the world, the ancient city, only discovered in 1911 by a National Geographic expedition under Hiram Bingham, is stunning.

That the Incas built this city out of rock at 8,000 feet, on a ridge covered in forest and flanked on both sides by precipitous drops of thousands of feet to the Urubamba, was truly an amazing feat.

Some 40 percent of the site has been re-built, but most notable is the exquisite stonework the Incas employed for their important structures, especially temples and other religious buildings, which have withstood the depredations and erosion of time admirably.

Fortunately, the conquistadors never found Machu Picchu. But the Spanish conquerors, who killed the last Inca ruler and were determined to erase all traces of Inca civilization to make way for their Christian structures, in many cases just left the Inca stonework as a foundation on which to build their churches and palaces, as you can see at many sites in Cuzco.

The Peruvian Andes lie in the center of what is, "one of the great hotspots in the world for biodiversity," says Roger McManus, the director of the Center for Conservation and Sustainable Development at the Missouri Botanical Garden, in St. Louis.

Tourism Minister Conseco

Peru is number one in biodiversity in the world, McManus says. "It has incredible biological diversity, coupled with environmental cultural diversity," he adds. But few know of its treasures: "It is one of the greatest undiscovered places in the world," he says.

MBG will help Cuzco University increase its meagre collection of 3,000 plants to tens of thousands of species, McManus says.

He describes Peru as an "evolutionary cauldron" produced by the confluence of various ecosystems created by a unique combination of elevation and moisture. Some 308,000 foreign tourists visited Machu Picchu last year, according to Jose Koechlin, who owns the Pueblo Hotel and has since the 1970s been actively involved in developing tourism in the area.

Of these, 80,000 made the four-day trek along the Inca Trail, which starts upstream and ends at Machu Picchu.

Koechlin says that only a decade ago a mere 50,000 tourists made it to the site, because the facilities were so undeveloped. The potential is still much greater, however.

Five years ago an American company, Wright Way Engineering, studied the tourist potential of Machu Picchu and determined that the site could handle 2,500 visitors at one time, in other words well over a million a year, given proper management.

The other great tourist destination in Peru is the Amazon and its rain forests, but this is still largely undeveloped.

However, the government currently is promoting a major tourist development on the northern coast, where warmer waters make a beech resort possible.

Tourism Minister Raul Diez Conseco, who is also vice president of Peru, says the government will invest up to $45 million in infrastructure for the project at Playa Hermosa, supported by loans from the Inter-American Development Bank.

The government is wooing the private sector to pour in as much as $150 million in investments for the construction of 10 resort hotels, a marina and other facilities.

This project is part of a government effort to increase tourism from under a million a year today to three million by 2006. Tourism employs more people per dollar invested than any other industry.

But Peru has never been a sun and sea destination and some key players in the tourism industry are concerned that adding a new element to the tourism mix might dilute precious resources from developing the main attractions: Cuzco/Machu Picchu and the rain forests.