Ah, the Mediterranean: brilliant sun, snow-white sand, a smattering of paradisiacal islands in a glittering sea. That’s the reputation that makes the region the most popular tourist destination in the world — but sadly, the flood of tourists is rapidly unmaking the reputation. Every year, the region hosts 200 million visitors — nearly one-third of the world’s tourist flow, and more than a three-fold increase since 1970. Hotels, marinas, and cruise-ship ports have sprung up to accommodate them, effacing much of the region’s famous coastline. Other environmental problems abound as well: Half the region’s wastewater is dumped into the sea untreated, triggering algae blooms that create dead zones in the sea; almost 600,000 tons of oil are spilled into the blue waters every year, mostly from illegal cleaning of ship tanks; and commercial fish are declining from overfishing and habitat loss. “If we follow this trend, there will be no natural spaces left by the end of the century,” said Lucien Chabason, coordinator of the U.N. Environment Programme’s Mediterranean Action Program in Athens.