Tourism is now among the world's most important industries, generating jobs and profits worth billions of pounds. At the same time, however, mass tourism can have dire effects on the people and places it embraces — both tourists and the societies and human environments they visit. We are increasingly familiar with some of the worst effects of unthinking, unmanaged, unsustainable tourism: previously undeveloped coastal villages that have become sprawling, charmless towns. Their seas poisoned by sewage, denuded of wildlife, their beaches stained with litter and empty tubes of sun cream. Historic towns, their streets now choked with traffic, their temples, churches and cathedrals seemingly reduced to a backdrop for holiday snaps that proclaim, 'Been there, Done that'. Some of the world's richest environments are bruised by the tourist onslaught, their most distinctive wildlife driven to near-extinction, with wider environmental impacts caused by the fuel-hungry transport systems used to take holidaying travellers around the world and back again. Less appreciated, perhaps, is the social dislocation unsustainable tourism can cause: once-cohesive communities disrupted as the holiday industry replaces old crafts, turning fishermen into tour boat operators, farmers into fast-food stores or hotel cleaners. Even the tourists are affected, the most placid and tolerant of us becoming short-tempered and exploitative. All too often, clutching our soon-to-be-discarded souvenirs and cursing late flights and anybody who doesn't speak our language, we arrive home muttering: 'After that, I need a holiday!'