represents the biggest natural reserve in Vietnam: Hoang Lien Son National Park. the park cover in nearly 30,000 hectares and is unique in south-east Asia for its tiered forest ecosystems. it contains over 2,000 plant species and about 500 animal species , among with the black gibbon, of which features of the landscape immediately attract the vistor's attention: the terraced rice fields on slopes in staircases and the innumerable limestone peaks and crests emerging from the clouds in the morning, a sort of halong bay transferred to the mountains