April 10-17, 2006 issue - When Ernest Hemingway wrote "The Snows of Kilimanjaro," a holiday outing was the last thing he had in mind. Who could have known that this classic tale about a failed writer dying of gangrene in the shadow of Africa's tallest mountain would spark a stampede? Every year, some 10,000 vacationers huff their way to the 5,896-meter peak that untold tour operators have flogged with Hemingway's majestic words: "Wide as all the world, great, high, and unbelievably white in the sun." So it's poetic justice of sorts that the travel industry's purloined icon is melting. Thanks to global warming and deforestation, the millennial snowcap that was said to cover King Solomon's tomb is receding. Scientists say that within 15 years, Kilimanjaro's storied glaciers will be history. Soon the brokers of wanderlust may be spinning the prose again to hawk the ultimate vacation: "Last chance to see the snows of Kilimanjaro."

Those vanishing snows are emblematic of travel in a worrying new time—when no place can be taken for granted anymore. No matter how exotic the destination, until recently a traveler's biggest concern was how to get there, not where the journey would ultimately lead. Now thanks to rising incomes and falling airfares, getting there is the easy part; last year a record 806 million tourists hit the road. But those hordes—combined with forces ranging from climate change to civil war, industrial toxins to runaway development—are laying siege to some of the world's most treasured and irreplaceable sites. Whether the millennial gates of Machu Picchu or the moonlit waterways of Venice, we are in danger of losing places we thought would always be around, sure as Stonehenge. New Orleans nearly drowned. The Coral Triangle, a diver's paradise, is as fragile as an eggshell. Visitors ride go-karts along the Great Wall of China and steal artifacts from the crumbling temples of Luxor. Even Stonehenge has been cordoned off. The only certainty for today's travelers is that the wonders of the world are perishable, whether they're made of stone or ice, by man or nature.

The number-one threat to tourist treasures, paradoxically, is tourism itself. The challenge is how to keep the world's most esteemed monuments from being loved to death. "Tourism carries a tremendous potential that must be acknowledged as essential for the future of world heritage'," says Bonnie Burnham, president of the World Monuments Fund (WMF). "But without proper management we can easily get out of control." For all Hurricane Wilma's wrath, patching Cancún back together will be easy compared with taming the monster that the tourist economy has unleashed. The 7 million visitors a year who descend on this megaresort and surrounding patches of the Mexican Caribbean coast already represent a conservation nightmare, straining water supply, sewers, and marine life. And it's not just Mexico. Conservation International reckons that "unsustainable tourism" poses the main threat to half the cultural heritage sites in Latin America and the Caribbean, and to one in five sites in Asia and the Pacific. Cambodia's once-remote Angkor temples now receive a million visitors a year; the Taj Mahal is subject to 7 million. Rising prosperity in the developing world, more and more elderly on the move, and cheap flights to anywhere will only hasten the human flood. China alone reported a staggering 1.1 billion domestic tourists in 2004.

Our wanderlust is not solely to blame, however. Popular tourist destinations have been hit in the last few years by glacier-withering global warming, an epic tidal wave and a harem of tropical storms in the Caribbean. Worse, avian flu is on the loose. Before leaving home the future holidaymaker may be obliged to consult not only the exchange rate and the Weather Channel but the Tsunami Warning Center, Jane's Terrorism Watch Report ("your daily update on terrorist activities worldwide") and Citigroup's Pandemic Sensitivity Index. The hazards have not been lost on the travel industry, the world's largest earner of foreign exchange. For the first time, the World Trade and Tourism Council (WTTC) will dedicate an entire session of its annual summit, to be held in Washington next month, to health and natural disasters. "Whether it's natural or manmade catastrophes, this is the reality,'' says WTTC chairman Vince Wolfington. "And more and more we're going to have to deal with it.''

It is a daunting task. The WMF list of the 100 most endangered world heritage sites spans 55 countries. Topping the list: Iraq—not the Iraq Museum or the Al Askariya shrine, but the entire country. Never mind the obvious threats, like terrorism, war or sectarian strife. Forces like global warming pose subtler challenges. The United Nations University recently reported that the number of annual catastrophes provoked by "extreme weather" and water-related emergencies has tripled since the 1970s, while economic damage increased sixfold. By now everyone knows that Venice is drowning, but even such apparently untouchable monuments as the Tower of London and the adobe mosques of Timbuktu are also vulnerable, thanks to the flash floods and rising water tables caused by global climate change. While Bourbon Street was tidied up in time for Mardi Gras, so much of the rest of New Orleans remains in shambles that hotels have been forced to cede rooms to homeless employees. The whole city has been added to the WMF's most endangered list.

The threats have literally reached the ends of the earth. Most holidaymakers shiver at the thought of a trek to Antarctica. Not Tom Ritchie. "To be in a small boat and see a huge humpback whale come up and look at you is a spiritual interaction," says Ritchie, a guide for Lindblad Expeditions. Today travelers shell out up to $50,000 for a romp on the White Continent—a small price to pay for an opportunity that may not be around in 30 years. Scientists report that 212 of the 244 glaciers necklacing the Antarctic Peninsula have retreated as temperatures have risen more than 4.5 degrees Fahrenheit in the past 60 years. Whales and penguins that feed on krill and coldwater plankton may soon be gone—along with one of the world's most cherished photo ops.

Predatory economic development has done its share of damage as well. The tower at the Helsinki Malmi international airport is a gem of 1930s modernist architecture, but if city developers have their way, it will be razed to make way for a 10,000-unit suburban housing complex. If saving a building sounds daunting, think about rescuing an entire city. If Mexico City (population: 18 million) keeps on sucking up ground water at the current clip from the city's aquifer, the world's largest megalopolis—which also happens to contain the world's finest pre-Columbian ruins—is certain to sink into the clay. No wonder all of Mexico City, too, has been relegated to the WMF's endangered list.

Nor is the Old World safe from the ravages of the modern. Though seismologists say that Vesuvius will erupt again sooner or later, hot lava may be the least of the worries facing Naples, a city of 1 million nestled in the volcano's shadow. In its glory, in the 17th century, Naples was Europe's largest city after Paris and every bit as cosmopolitan. These days, Naples might look more like a postcard for urban decadence. Chaotic traffic has pumped so much poison into the air that the facades of medieval buildings are disintegrating. Urban hucksters hurl up four clandestine buildings for every legal one, turning this U.N. World Heritage site into a boneyard of scaffolding. "See Naples and Die," the Bourbons once boasted during Naples's golden age. Skeptics have a new saying: "See Naples before it dies."

The good—and bad—news is that tourists come from hardy stock. Just a year after the Asian tsunami swallowed hundreds of kilometers of South Asian beachfront, vacationers came streaming back. Sometimes calamity can be turned into opportunity. "There definitely is a rush to see and explore the world before it changes,'' says Matt Kareus of Natural Habitat, which operates excursions to Antarctica. Archeologists and green groups blame the massive Three Gorges hydroelectric dam for destroying untold centuries-old cultural splendors, but Chinese sightseers line up to snap pictures from the concrete ramparts. Even the empty space where the World Trade towers once stood has become a tourist attraction. "We are all aware the world is more unpredictable," says Julio Aramberri, professor of tourism at Philadelphia's Drexel University. "But tourism is much more resilient than you'd think."

Managing the onslaught is now a topic of fierce debate. "Sometimes it takes coming to the brink of loss to make people recognize what they value," says Burnham. Listing endangered sites helps raise their visibility and rally local support, but can also backfire by unleashing more tourists for a final antediluvian glimpse. Steeper admission prices help, but are blatantly biased toward travelers with deeper pockets. Some experts are turning to crowd engineering, such as timed tickets, a technique that many museums and Disney World mastered years ago. UNESCO's World Heritage Centre channels money to safeguard sites, while the WMF works with local governments, civic groups and the private sector to restore imperiled monuments.

The debate is hardly academic. By now it's apparent that travelers may be spooked, delayed or detoured, but not deterred. Despite the chain of calamities, more people than ever left home on holiday last year, and experts are confident the numbers will continue to grow. A world awash in tourists can be a curse for its endangered treasures, or a source of funds to save them. Getting the balance right could be the difference between future generations beholding the living wonders of the world, and merely reading about them in a story book.

With Barbie Nadeau in Naples, Sana Butler in New York and Quindlen Krovatin in Beijing

April 10-17, 2006 issue - In 1240, the Holy Roman Emperor Frederick II built his military fortress, Castel del Monte, on a lonely hill in central Puglia, where he had a perfect view of approaching enemies. He probably never envisioned it would become a major destination—or that the enemies might be tourists. But these days, the old castle has been polished clean, and hundreds of multicolored Pullman buses snake up the winding roads to its grounds, now scattered with T-shirt stands, Coca-Cola signs and a 200-car parking lot. In fact, all over this usually desolate part of southern Italy, tourists scurry between such stops as the conical trullo houses in Alberobello and the cave ruins of Matera in nearby Basilicata—all sites few would have heard of if not for the fact that the United Nations Educational, Scientific and Cultural Organization (UNESCO) has christened them World Heritage destinations.

Officially, UNESCO bestows the honor on places that exemplify an area's ancestry, with the purpose of ensuring they are preserved. Unofficially, designation is a kind of fairy dust that often turns little-known cultural gems into overnight tourist sensations, fostering intense competition among places to get listed. That is not always a good thing. "Sometimes a site becomes so attractive it becomes impossible to visit or appreciate," says Francesco Bandarin, director of the UNESCO World Heritage Center. "This is the big problem in generating tourist traffic."

Indeed, there is growing concern that World Heritage designation may in the end do more harm than good. Lisa Mastny, senior adviser to the World Watch Institute, says tourism is a double-edged sword for places considered of "outstanding value to humanity. It offers many impoverished communities the chance to reap financial rewards, but also threatens the very resources—human and natural—upon which the industry is ultimately built." The already popular Mayan ruins of Chichén Itzá in Mexico, for example, saw a massive influx of tourists after UNESCO declared them a World Heritage site in 1988. With more than 5,000 visitors a day, the ruins have turned into a Disney-esque mecca. Worse, they are being sorely threatened by the wear and tear of relentless foot traffic, not to mention outright vandalism.

The biggest problem is that there is virtually no money attached to World Heritage status. After places win the designation—a laborious bureaucratic process that takes nearly five years from the time they are nominated—they are left on their own financially. Funds are available from the World Heritage Trust in the form of loans, or through private organizations like Ted Turner's United Nations Foundation. But competition is fierce; in the 27 years since UNESCO designated the first 12 World Heritage sites, the list has grown to 812 today. Under smart government management, some of the increase in tourist dollars is invested in preserving the sites—as in Rome, where visitors' entrance fees go directly into maintenance.

But Rome is an anomaly. The majority of World Heritage sites are in developing countries, often besieged by corruption, civil strife and extreme poverty. Furthermore, natural or manmade disasters can thwart even the best-laid plans. The Iranian government, for instance, was unable to recover from the earthquakes that destroyed the cultural heritage site of Bam last year. Australia's Great Barrier Reef and Nepal's Mount Everest, both World Heritage sites, are considered endangered due to climate change, which cannot be reversed by single governments.

There is growing awareness that assigning UNESCO designation is worthless—or worse, counterproductive—without some kind of follow-up preservation program. "In the early days there wasn't much attention given to what would happen once these sites became World Heritage," says Joseph King, director of the sites unit at the International Centre for the Study of the Preservation and Restoration of Cultural Property (ICCROM), based in Rome. Slowly, that's changing. In sub-Saharan Africa, a 12-year training program called Africa 2009 is currently underway to teach locals not only how to preserve their immovable cultural heritage, but how to use it for economic development. In Eastern Europe, where tourism is a relatively new commodity, cities are looking for help in figuring out where to draw the line between preserving historical centers and fostering urban development. Tomas Hajek, director of the Czech National Monument Protection Office, favors allocating one specific district as a commercial center and concentrating all new buildings there. "Prague will lose its magic if we allow tall modern buildings to blot the skyline," he says. "Being included in the UNESCO list is a safeguard for protecting our heritage—although there is very strong pressure from developers."

For its part, UNESCO is trying its best to turn all 812 World Heritage sites into exemplary models of preservation. The irony, of course, is that it needs tourism to do it. It has recently teamed with companies like Expedia and Jet Tours in an attempt to market World Heritage site tours, and, more important, to teach tourists to be responsible when visiting these places. It has also worked with ICCROM and other agencies to lobby guidebook editors such as Michelin and Lonely Planet to include an instruction page for visiting heritage sites. Among the obvious tips they want to promote: "Don't remove any artifacts" and "Don't mock the locals." "It's important for the tourists to understand that these sites have been there a long, long time," says ICCROM's King. And with some effort, they'll remain for a long time to come.

With Katka Krosnar in Prague