Con Dao Islands

A remote archipelago of 16 islands 230 kilometres off the southern Vietnamese coast, Con Dao was Vietnam's most notorious prison colony from 1862 to 1975 -- where 20,000 Vietnamese independence fighters, including future Communist Party leaders, died in the so-called Tiger Cages. Today the same islands contain Vietnam's finest national park, with nesting leatherback sea turtles on protected beaches, dugongs feeding in seagrass meadows, and coral reefs ranked among the most pristine in Southeast Asia by the World Wildlife Fund. Outperforming #2 Ha Long Bay for ecological untouchedness, it remains 70% less visited than its northern rival.