Ha Long Bay

A UNESCO World Heritage Site since 1994, Ha Long Bay contains 1,969 islands and islets formed from karst limestone over 500 million years, rising dramatically from emerald water to create one of the most otherworldly seascapes on Earth. The bay covers 1,553 square kilometres in the Gulf of Tonkin and is best explored by overnight cruise, where passengers wake at dawn surrounded by limestone pillars shrouded in mist -- the defining image of Vietnamese tourism used in virtually every promotional campaign since 1990.