The waters of Ha Long Bay are not as clean as they may appear in photography. The waste from hundreds of tourist boats is the main source of water pollution in the bay. Halong Bay is located in northeastern Vietnam, between longitudes 106 ° 56 'and 107 ° 37' East and latitudes 20 ° 43 'and 21 ° 09' North.
The bay is located in the Yên Hưng district, between the city of Hạ Long and Cẩm Phả, up to the Vân Đồn district, bordered to the south and south-east by the Gulf of Tonkin, to the north by China and to the west and south- west with the island of Cat Ba.
The bay occupies 120 km of coastline and covers an area of approximately 1,553 km², with approximately 1,969 islets. The UNESCO protected area includes about 434 km² and 775 islands, the core of which is delimited by 69 points: the island of Đầu Gỗ to the west, Lake Ba Hầm to the south and the Cống Tây island to the east.
The protected area extends from the fuel depot of Cái Dăm to the municipality of Quang Hanh. The bay contains a dense concentration of 1969 monolithic limestone islands, each covered with dense vegetation, rising from the ocean.
Many of the islands are empty, and contain huge caves. Hang Đầu Gỗ contains the largest cave in the bay. French explorers visited it in the 19th century, calling it Grotte des Merveilles. Its three large chambers contain numerous large stalactites and stalagmites (as well as 19th-century graffiti).
There are two large islands, Tuan Chau and Cat Ba, with permanent settlements. Both of these islands have tourist facilities, including hotels and beaches. There are also very beautiful beaches on the smaller islands. Some islands are home to floating fishing villages that scour the shallow waters for 200 species of fish and 450 species of shellfish.
Most of the islands got their name from their shape: among them are Voi (elephant), Ga Choi (fighting claw) and Mai Nha (roof). 989 islands have been given a name. Among the animals that inhabit them are antelopes, monkeys and iguanas.
In 1962 the Vietnamese Minister of Culture, Sports and Tourism declared the bay a National Renowned Lanscape Vestige. It was listed as a UNESCO World Heritage Site during the Committee's 18th Congress in Phuket, Thailand, on December 17, 1994, for its aesthetic value.
On 2 December 2000, during the 24th congress in Cairns, Australia, geological and geomorphic value was added to the reasons. On August 8, 2008, Ha Long became one of the Seven Natural Wonders of the World according to the New Open World Foundation.
A local legend says that many years ago the Vietnamese were fighting the Chinese invaders; the gods sent a family of dragons to help them. These dragons began spitting jewels which transformed into the islands and islets that dot the bay, then uniting them to form a wall against invaders.
People saved their land and turned it into what would become Vietnam. The place where the mother dragon landed was called Hạ Long, the place where the sons arrived took the name of Bái Tử Long (Bái: following, Tử: sons, Long: dragon), and the place where the sons violently waved their tails and was called Bạch Long Vỹ.