In the brochure or guidebook they look idyllic and fascinating. Unspoilt beaches, ancient monuments and historic cities dripping with charm. But the Wish You Were Here postcard scenes of the world's tourist sites do not show you an increasingly common sight: the band of placard-waving locals who wish you weren't.
Last week the Chilean under-secretary of the interior, Patricio Rosende, travelled more than 2,000 miles to a volcanic speck in the ocean to spend two days in heated talks with the people of Easter Island. Those who live on the island, which is part of Chile and famed for its massive ancient stone statues, believe they are facing ecological disaster because of hordes of tourists. But their complaints have fallen on deaf ears and lack support from those on the island who survive on visitor dollars.
Last month, protesters resorted to blocking the airport, moving tents and trucks on to the runway and demanding that the 65,000 visitors who fly in each year, some of whom choose to stay on and work, be capped. As about 600 angry US tourists expressed their irritation after they faced the resultant flight cancellations at the airport in the Chilean capital, Santiago, the government agreed to discuss the islanders' concerns about overcrowding, the environment and controls on commerce.
"The only thing we are looking for is an answer from the government regarding the need for greater control on who comes to Easter Island," said the island's mayor, Luz Zasso. "We ask, for example, that those who arrive have a card which describes the activity they will be doing here, just like in the Galápagos Islands."
With a population of 4,900 that has grown by 29% since 2002, the island is forced to deal with more than it can handle. A similar problem led to the Pitcairn Islands, also in the Pacific, establishing immigration controls, with categories for "short-period" tourists with a maximum stay of 14 days and "long-period" tourists with a maximum stay of six months.
The Galápagos Islands already have a limit on visitors but still suffer from what some call backpacker fatigue. Only a few weeks ago British and Ecuadorian scientists discovered that a mosquito carrying avian malaria that threatens the unique ecosystem of the islands was being brought in by tourists. The discovery may help local environmental activists, who are hugely concerned about the future of the islands, which two years ago were added to the list of 31 endangered world heritage sites by Unesco.
The Galápagos – an archipelago in the Pacific famed for its huge number of endemic species – saw an increase in the number of visitors from 40,000 in 1990 to more than 170,000 last year, making tourism a major source of income for the islands and mainland Ecuador. In 2007 there were 2,194 flights to the islands and an estimated 363,000 passenger days on boats.
"Few tourists realise the irony that their trip to the Galápagos is putting strain on the very unspoilt beauty they are there to see," said Tom Hall, of the travel guide Lonely Planet. "Tourism round the world is facing some really pressing issues. We are seeing these few demonstrations by locals, but really if you are in a developing country and are worried about these issues you are also going to be worried about your income and about rocking the boat with your government," he said.
"Easter Island is a little different to the Galápagos and a little more complicated. It's a key stopover for flights between Chile and Tahiti, and gets a lot of visitors stopping over for a few days. It's part of many popular round-the-world itineraries for independent travellers and flights here are usually full.
"Owing to this, it doesn't have the option of restricting numbers by aiming at top-end tourists as some countries do – Botswana, for instance. The flip side of that is there are only so many of those tourists to go around. Then places such as Australia market themselves as independent traveller destinations and accordingly have to deal with the problems that brings. The remoteness of Easter Island means it'll never be another Machu Picchu [the Inca mountain city in Peru] in terms of the numbers who visit, but it is almost entirely reliant on tourism so locals are understandably keen to draw attention to and limit any damage.
"High-volume tourism changes places, but you look at what Venice is planning – and is that fair? Should one of the most expensive cities in the world have the right to keep people out?"
What Venice is planning is still very much at the discussion level, but pressure is growing on Italian authorities to take drastic action against the daily influx of visitors who crowd the city's narrow streets and Renaissance square.
Enrico Mingardi, in charge of public transport in the city, has just proposed that tourists should have to pre-book their visits to the city and only so many would be admitted on any one day.
"There's a need to study a project where there is a cap on the number of visitors," he said. "If you have a booking, you can come in; if not, you can't. There is a physical threshold above which we cannot go."
Others in the city have called the plans "undemocratic". Alessandra Smith, a spokeswoman for the Italian State Tourist Board, said an alternative was to encourage people away from the traditional sights. "Venice is not just St Mark's Square, there are areas off the beaten track you can find fewer people… Areas such as what used to be the old Jewish ghetto and quarters, or the island opposite St Mark's Square, are very pleasant. You can explore the old churches and the old docklands; all those areas off the square are much quieter."
But the truth is that there are a decreasing number of quiet spots around the world not being reached by the 903 million pairs of feet that criss-crossed the planet on their holidays in 2007 alone.
Ever since the guidebook to foreign lands became fashionable in Victorian times, tourism has risen steadily. With China and India coming on to the world stage, too, as many more of their citizens catch the travel bug, numbers of tourists have risen steeply year on year for the past five years.
Brazil, Middle East, France, the United States, and even Armenia reported bumper figures for tourism last year. Many blame guidebooks and travel writing for encouraging the boom, but the truth is that when Ernest Hemingway wrote The Snows of Kilimanjaro, he had no idea he would encourage more than 10,000 people to tackle the eroding sides of the Tanzanian peak. Likewise the conquering of Everest has seen a small but devout stream of climbers leave so much litter there that the base camp was described as "the world's highest garbage dump" by mountaineer Sir Chris Bonington.
Clear-up efforts were finally put in place after pressure from local sherpas and the Nepal Mountaineering Association encouraged the Nepalese government to impose a deposit on climbers, refundable only if they take disposable equipment back home with them.
Even the UK has not been immune to the problems, with the standing stones at Stonehenge having to be fenced off from the hands of an over-eager public to prevent damage. Ancient monuments are often particularly vulnerable. When the builders of the tombs of the pharaohs closed the burial places in the Valley of the Kings, they did everything they could to seal them for all eternity.
Ventilation was not a big priority, which is why Zahi Hawass, secretary general of Egypt's Supreme Council of Antiquities, announced in August that the impact of thousands of tourists every day breathing inside the tombs was causing damage to wall carvings and paint. The grave sites of the boy king Tutankhamun and of Queen Nefertiti and Seti I have so much humidity that fungus is growing on the walls. The Egyptian authorities are now expected to announce plans to close at least those three tombs down to the public completely, replacing them with replicas.
Otherwise, Hawass warned, they would be gone: "The tombs which are open to visitors face severe damage to both colours and the engravings. The levels of humidity and fungus are increasing because of the breath of visitors, and this means that the tombs could disappear in between 150 and 500 years."
The mummy of Tutankhamun, who was made pharaoh at the age of nine, was found in an ornate sarcophagus, his face covered by a solid gold burial mask encrusted with semi-precious stones. It was his image, and the story of his mysterious death in 1324BC at the age of 19 that helped Egypt to sell itself as a tourist destination across the world.
Egypt's Supreme Council of Antiquities has taken a series of measures to protect the tombs, including restrictions on visitors. The country has come a long way in tackling environmental damage since 1995, when it had to be dissuaded from building a motorway alongside the pyramid of Khufu at Giza, the last of the ancient seven wonders of the world still standing – although earthquakes rather than tourism saw to most of the rest.
Tourism can be seen as either a source of funds to save such sights or the curse that erases them, but at the moment, said Xavier Font of Leeds Metropolitan University's Centre for Responsible Tourism, the right balance is far from being struck. "Around the world, most governments can point to one project where the environment has been considered and the locals are happy, but for every one like that there will be another 10 some 20 miles down the road where the turtle habitat has been destroyed or forests ripped up.
"The problem is in the actual development itself, which has the major impact, and with construction companies building resorts and second homes they are going to sell straight on to operators. There is little impetus to build them with any environmental conscience, when actually it is quite simple to put in measures that will reduce a building's water and energy use. There is a cycle of damage that tourism brings; that's true whether it's Brazil or Benidorm. Places like the Red Sea are using so much water they need a desalination plant. So they put one in, but in the process they over-salinate that area and kill the coral.
"Much of the so-called income generated by tourism goes outside the country to big companies and operators. The people who are crushed by tourism will be the very ones tourists think are getting the money. The reality is the farmer may sell his land to the developer, but then the tourists move in and the price of living becomes so high the farmer can't afford to be there any more."
Not only are we doing damage by thoughtless travelling, he said, we also use more energy and resources on holiday than we do at home.
A rise in eco-holidays and sustainable travel operators may go a little way to addressing the balance but, as more and more tourism sites round the world face backpacker fatigue, some of the world's most famous wonders could increasingly be closed off to the public, accessible only through an image on a postcard.
