Think about a lagoon, hidden from the sea and passing boats by a high, curving wall of rock. Then imagine white sands and coral gardens never damaged by dynamite fishing or trawling nets. Freshwater falls scatter the island, surrounded by jungle - not the forests of inland Thailand, but jungle. Canopies three levels deep, plants untouched for a thousand years, strangely coloured birds and monkeys in the trees. On the white sands, fishing in the coral garden, a select community of travellers pass the months. They leave if they want to, they return, the beach never changes.