Every visitor to Greece is familiar with the iconic images of Santorini – those blue-domed churches looking out over the caldera sunset view. But what image do you get if you point your camera in the opposite direction?

From April to October, the pretty paved pathways decorating the cliff face at Oia, the village famous for its sunsets, is packed with thousands of visitors all whipping out their smartphones to take the exact same picture. “In peak season, it’s busier than Penn Station at rush hour,” says the island’s former mayoral advisor, Lukas Bellonias.

Over the past five years, Santorini has become one of the most popular destinations in the world – overnight stays here have increased by 66 percent. And although it’s made the island into a rare financial success story in a country still struggling with the fallout from its decade-long financial crisis, it’s also taking a toll. A recent report on “overtourism” by the EU’s transport committee warned that the island is failing to manage the increasing numbers, spelling disaster for the local community and the environment, and putting “the future of the destination at risk.”

According to Bellonias, this steep rise in visitors has been driven by social media. “Santorini has a unique geography that people immediately want to photograph,” he explains. “Before, you’d only show vacation photos to your close friends and family. But now, people share them with thousands.” The cobbled streets of Oia have now become a fixture on many an Instagram influencer’s feed. During peak summer months, according to Bellonias, mobile network companies struggle to provide enough coverage for the amount of people taking and uploading images.

Bellonias was part of an administration that tried for years to sound the alarm about the situation, before they were voted out of office in May 2019. “Everything has a capacity,” he explains. “Each island can only accommodate a certain number of people.” In 2018, they introduced an 8000-person daily cap on cruise visitors. But Bellonias tells me that far more action is needed, and the municipality does not have the power to make it happen.

“Look,” he says, opening up Google Earth on his computer. “Twenty or thirty years ago there was a village here and a village there,” he says, pointing to the sprawling mass of buildings now covering most of the island’s west coast. “In five to ten years, it could end up as one big city.” The municipality has no power to stop new buildings going up. That responsibility lies with the Santorini Building Authority, which is controlled by central government. The EU report is highly critical of the Greek government, citing its “lack of adequate and appropriate governance” and its failure to implement planning legislation on Santorini.

“We can’t forecast the results of this but it’s certain the quality of life will decrease,” says Bellonias. “We’ll have problems that we usually only see in cities.” The island is already plagued by traffic jams in the summer months, and Airbnb has pushed up housing prices so much that employers are having to build new accommodation just for their staff.

“There’s a minority [on the island] that really understands these problems and really wants a more sustainable way of managing the island, but many don’t,” he says. “The interest of the whole conflicts with the interest of the individual.”

One resident campaigning for a better future for Santorini is Michael Ermogenis, a Greek-Australian who has lived on the island for the last 12 years. He is the founder of the Save Oia campaign, which raises awareness of the need for more sustainable management of the island.

“Essentially, Santorini is the front window of Greece,” he tells me. “But you’d think that people would look after their own front window – hire cleaners, security. None of that happens.” He is particularly angry over what he sees as the exploitation of the island by multinational companies. “When there’s demand like this, everyone wants a piece of it,” he continues. “All the cruise ships, all the tour operators, anyone who’s got anything to sell will use it.” He explains that the much-maligned day-cruise visitors come on all-inclusive tours, meaning they add to the crowds but “don’t even buy a postcard.”

Ermogenis has begun hanging “Respect” signs around Oia, reminding visitors: “It’s your holiday… but it’s our home” because, he says, “people behave not just badly, but unbelievably so. They treat churches like selfie studios. I’d get woken up at 6am by people traipsing across my terrace.”

To understand how Santorini has reached this point, it’s worth taking a look at its past. The island was once one of the poorest and most isolated in Greece; boats from the mainland took two days to reach it. The cave houses carved into the cliff face were created because residents had few building materials. A devastating earthquake in 1956 destroyed over 500 homes and sparked a mass exodus. And then came tourism. “The people here went from having nothing to, within two generations, holding the keys to Fort Knox,” says Ermogenis. “They have this incredible gift from nature. But they’re clueless about how to manage it.”

The island’s famed geography was formed by eruptions from a still-active volcano. Knowing that it could still destroy everything has, arguably, instilled a sense of impermanence in its inhabitants, a feeling of carpe diem. Doesn’t it make sense to squeeze as much money out of what you have while you still can?

Other industries that have existed on the island, like farming and wine production, are also under siege. Yannis Valambous, owner of local winery Vassaltis Vineyards, says that the grapes he uses to create blends have quadrupled in price because vineyard owners are building vacation accommodations on their land or selling it off. “I don’t blame people here for wanting to make money; they had nothing for so long,” he says. “But it’s getting to the point where I’m worried it will have the adverse effect, and put visitors off coming.”

The constant building and the floods of tourists create tons of rubbish. Santorini, however, still has no proper waste-management facilities, so every bit of trash goes into a huge dump that doesn’t meet EU regulations. Leakage has the potential to affect the surrounding earth, water and air. Bellonias says that every plan for a new landfill site has been rejected by residents who don’t want it near their homes or businesses.

Out of ideas and with little power to bring in new policies, the muncipality’s most recent strategy has been to promote the island as a year-round destination “in order to ease pressure in the summer months.” Of course, this brings with it the risk that crowds will stick around for even longer. What about, I ask Bellonias, introducing more caps on visitor numbers, or a tourist tax? “We could, but how would it work? Say someone wants to honeymoon in Santorini; how do we tell them they can’t come here?”

As the debate rages on, the crowds of travellers continue to line up in front of the caldera, posing for pictures with their selfie sticks in hand. No one knows for sure what the future of Santorini will be. But for those of us still keen to see it for ourselves, there are steps we can take. We can visit outside of peak season, not take a day cruise, choose eco hotels over Airbnbs and make every effort to reduce our waste. We all have a part to play in preserving this unique gift from nature.

A version of this article originally appeared in The Economist’s sister magazine, 1843.