MACHU PICCHU, Peru — Darwin Camacho, tour guide and denizen of this place for a quarter of a century, gestures toward gaps in the famously precise stonework of an Inca wall.

"The stones are separating," he says, pointing to the fissures separating blocks once snugly fit together by craftsmen toiling without wheel or cement. "Something needs to be done about this…. "

Camacho proceeds to the granite pillar known as the Intiwatana, or "hitching post of the sun," a sacred artifact chipped in undignified fashion when a 1,000-pound mechanical arm crashed on it during the filming of an ad for Peru's preferred cerveza.

"A beer commercial!" Camacho exclaims, pointing his umbrella at the damage like an accusing finger. "How irresponsible is our government to have allowed this!"

Machu Picchu, one of the most storied archeological sites in the Americas, has become a victim of its own astounding success and now faces threats from overcrowding, landslides, erosion, fire — and greed.

The end of a guerrilla war in Peru and the onset of relative political stability have sparked a virtual tourist frenzy here. Almost 700,000 visitors, 70% of them foreigners, visited the site in 2005 — nearly double the number in 2003 and close to a tenfold increase since 1991. A million-plus visitors a year seems not far off — quite a load for a place that, according to current research, may have housed only 700 people or so during its Inca heyday.

As Peru seats a new president and Congress this year, many will be watching closely to see how much the country's notoriously crooked political structure will stand up to an assertive tourism sector that frowns on talk of restrictions.

"The question is going to be whether Machu Picchu is treated as an extraordinary, nonrenewable resource that needs protection, or whether you use it to get the maximum amount of foreign currency in the short term," said professor Richard L. Burger, an Inca expert at Yale University and frequent visitor. "They're going to have to deal with the issue of how much you build it up before you destroy it. And there's no easy solution."

The onslaught of visitors is literally trampling the place to death — compacting the relatively shallow soil and destabilizing the iconic dwellings, temples, fountains and other structures, experts say.

A day after tour guide Camacho's lament, the site's chief archeologist, Alfredo Mormontoy, insisted that reports of Machu Picchu's imminent demise, including a controversial prediction of a massive landslide, had been greatly exaggerated.

"There's a certain amount of alarmism out there about the future of Machu Picchu," said Mormontoy, who spent the morning patching a landslide-damaged path to the Temple of the Moon. "We are working hard here for conservation, with the minimum of intervention and respect for authenticity."

To the legions who trek to this dreamscape annually, the mist-shrouded Inca citadel of Machu Picchu mostly lives up to its reputation as an enchanted sanctuary — the "lost city" that Hiram Bingham, a swaggering Yale man with a flair for self-promotion, stumbled across in 1911 while seeking the Inca civilization's final redoubt in the Andes.

"Pure bliss," said a dazed American wanderer in faded jeans and a loose blouse, who gave her name only as Jasmin, as she descended barefoot on a recent afternoon. "I wanted to absorb the energy through the soles of my feet."

The mystique only seems to grow even as Bingham's fanciful claims — among them that Machu Picchu played host to rites involving "virgins of the sun" — have been discredited. Recent research indicates that the site's role was probably quite prosaic, serving as a royal retreat before the ridge was apparently abandoned about the time of the Spaniards' arrival.

Some five centuries later, Machu Picchu has joined the global must-see shortlist, drawing jet-setters, backpackers, new-agers, eco-adventurers and regiments of package-tour travelers from Asia, Europe, the United States and elsewhere. Nestled in the mist-shrouded mountains at about 8,000 feet, on the cusp between the steamy jungle and the chilly high valleys, the place evokes mystery. For many, a visit to Machu Picchu is more of a pilgrimage than a tourist stop.

"I waited all my life to come here," said Liliana Diaz, 38, of Bogota, Colombia, who made the journey by wheelchair, with tour guides hoisting her up rough patches. "This is a wonderful moment for me."

Machu Picchu is relatively small and quite vulnerable, the major structures occupying a scant 25 acres — an area not much larger than the Staples Center in Los Angeles.

A place fabled for its remoteness — a quality that may have helped spare Machu Picchu from the depredations of the conquistadors — is today relatively accessible, though no road reaches here.

Almost all visitors arrive via the venerable PeruRail train, passing snowcapped peaks, furious rapids and Inca structures en route. Most passages cost $68 to $105 round trip from the former Inca capital, Cuzco, 75 miles to the southeast. Some well-heeled visitors opt for the luxury "Hiram Bingham" coach, at $495 round trip.

The beer-commercial incident in 2000 that damaged the Intiwatana underscored the image of a Peruvian government bent on sucking every last buck from its singular attraction.

The United Nations Educational, Scientific and Cultural Organization, known as UNESCO, threatened to remove Machu Picchu from its list of World Heritage Sites, prompting Peruvian officials to change course.

A new 10-year master plan shifts the focus from development to "sustainable tourism," which emphasizes preservation of land, monuments and cultural heritage.

Many remain skeptical.

"Unfortunately, there are some people whose attitude is, 'I'm doing business now and I could care less what happens later,' " said Manuel Bryce, a consultant to the state tourism agency in the capital, Lima, and a former tour operator in the region. "We can't let Machu Picchu become Disneyland."

Belatedly, Peru is making a push to divert visitors to some of its other sites and wonders, including ruins that predate Machu Picchu by a millennium or more. But none has the exotic cachet of the "lost city."

The outgoing administration of Peruvian President Alejandro Toledo, which assumed office practically in the shadow of Machu Picchu, branded this country "the land of the Incas" and set out on a much-publicized spat with Yale University over artifacts carted away by Bingham almost a century ago. That dispute remains unresolved.

Among the recommendations of the new master plan are capping the number of daily visitors at 2,500 — a number sometimes surpassed during the high season, which runs from July to September. But any move to limit visitors faces resistance from the powerful alliance of tour operators, hotel owners and others based in and around Cuzco, which has thrived as the gateway to Machu Picchu.

Some merchants fear prolonged shutdowns for repairs and renovation. Already, trekkers are banned every February from a portion of the Inca Trail, the 30-mile path to the ruins favored by the more adventurous. Trash, makeshift bathrooms and campsites, along with occasional muggings, have become a problem along the route.

Officials in Lima "must take the needs of local people into account," declared Oscar Valencia, mayor of "Machupicchu" village, a kitschy boomtown that has sprung up around the Aguas Calientes train station — the sole entry point to the ruins in the cloud forest, apart from the Inca Trail. The raging Urubamba River and its tributaries occasionally carry off the precarious dwellings of trinket hawkers. Two years ago, 11 townsfolk were killed.

From the village, a transport firm partially owned by the mayor buses tourists up a dozen switchbacks to the entrance of the ruins, via a landslide-prone, three-mile mountain road featuring better-not-to-look vertical drops. Beyond the diesel-belching traffic and scarring of the mountain, many worry about the possibility of a catastrophic accident. Proposals for a cable car or monorail system have stalled.

As the chief archeologist at the citadel, Mormontoy was recently overseeing the repairs on the washed-out trail to the conical peak called Wayna Picchu, which also leads to the spectacular Temple of the Moon. Such maintenance issues, he said, do not mean the entire site of Machu Picchu is likely to be lost anytime soon in a landslide — as a much-discussed Japanese study suggested in 2001.

"Nothing is imminent," said Mormontoy, whose father was a conductor on the Machu Picchu train.

Still, international teams have installed sophisticated monitoring equipment to check for tectonic shifts. Workers are applying water-resistant sealant to vulnerable sections of stone and patching the intricate Inca drainage system in an effort to limit persistent water damage from the more than 80 inches of rain that falls here annually. Authorities are also working with area farmers to reduce the risk of dry-season fires.

But it is the inexorable influx of people that probably represents the greatest threat.

"I was hesitant to come here, honestly, because I'd heard about all the crowds," Steven Lloyd, 24, a backpacker from Vancouver, said recently as he stood near a stone structure known as the Guard House.

"But, standing up here, I have to say, 'This place is amazing.' There are a lot of tourists, yes, but it's still going to be a while before there's a Wal-Mart here."

Andrés D'Alessandro of The Times' Buenos Aires Bureau and special correspondent Adriana León in Lima contributed to this report.