Ha Long Bay is an inlet located in the Gulf of Tonkin, in Vietnamese territory. It is part of Quang Ninh province and comprises about 2000 limestone islets with numerous karst caves. The bay is located 164 km east of the capital Hanoi, not far from the border with China. In Vietnamese the term "Hạ Long" means "where the dragon descends into the sea". It has been a UNESCO World Heritage Site since 1994.
A local legend says that many years ago the Vietnamese were fighting the Chinese invaders, and the gods sent a family of dragons to help them. The place where the mother dragon landed was this bay.