Halong Bay is a body of water of approximately 1,500 square kilometres in north Vietnam with a 120 kilometre coastline, in the Gulf of Tonkin near the border with China, and 170 kilometres east of Hanoi. "Vinh Ha Long" — Halong Bay — means "Bay of the Descending Dragon" in the Vietnamese language. Ha means "descending" and Long means "dragon" in Sino-Vietnamese. The bay consists of a dense cluster of 1,969 limestone monolithic islands, each topped with thick jungle vegetation, which rise spectacularly from the ocean. Several of the islands are hollow, with enormous caves. Hang Dau Go (Wooden stakes Cave) is the largest grotto in the Halong area. French tourists visited in the late 19th century, and named the cave Grotte des Merveilles. Its three large chambers contain large numerous stalactites and stalagmites (as well as 19th century French graffiti). There are two bigger islands, Tuan Chau and Cat Ba, that have permanent inhabitants. Both of them have tourist facilities, including hotels and beaches. There are a number of wonderful beaches on the smaller islands. Some of the islands support floating villages of fishermen, who ply the shallow waters for 200 species of fish and 450 different kinds of mollusks. Many of the islands have acquired their names as a result of interpretation of their unusual shapes: such names include Voi Islet (elephant), Ga Choi Islet (fighting cock), and Mai Nha Islet (roof). 989 of the islands have been given names. Birds and animals including bantams, antelopes, monkeys, and iguanas also live on some of the islands. Read more ... Hide detail... Halong Bay is a body of water of approximately 1,500 square kilometres in north Vietnam with a 120 kilometre coastline, in the Gulf of Tonkin near the border with China, and 170 kilometres east of Hanoi. "Vinh Ha Long" — Halong Bay — means "Bay of the Descending Dragon" in the Vietnamese language. Ha means "descending" and Long means "dragon" in Sino-Vietnamese.
The bay consists of a dense cluster of 1,969 limestone monolithic islands, each topped with thick jungle vegetation, which rise spectacularly from the ocean. Several of the islands are hollow, with enormous caves. Hang Dau Go (Wooden stakes Cave) is the largest grotto in the Halong area. French tourists visited in the late 19th century, and named the cave Grotte des Merveilles. Its three large chambers contain large numerous stalactites and stalagmites (as well as 19th century French graffiti). There are two bigger islands, Tuan Chau and Cat Ba, that have permanent inhabitants. Both of them have tourist facilities, including hotels and beaches. There are a number of wonderful beaches on the smaller islands. Some of the islands support floating villages of fishermen, who ply the shallow waters for 200 species of fish and 450 different kinds of mollusks. Many of the islands have acquired their names as a result of interpretation of their unusual shapes: such names include Voi Islet (elephant), Ga Choi Islet (fighting cock), and Mai Nha Islet (roof). 989 of the islands have been given names. Birds and animals including bantams, antelopes, monkeys, and iguanas also live on some of the islands. 

The bay was World Heritage listed by UNESCO at the 18th meeting of the Committee of the World Heritages of UNESCO (in Thailand on December 17th, 1994). It is one of Vietnam's most popular tourist destinations. Local legend says that long ago when the Vietnamese were fighting Chinese invaders, the gods sent a family of dragons to help defend the land. This family of dragons descended upon what is now Ha Long Bay (hence the name "Bay of Descending Dragons") and began spitting out jewels and jade. These jewels turned into the islands and islets dotting the bay, linking together to form barriers against the invaders. The people kept their land safe and formed what later became the country of Vietnam. A modern legend claims that a creature named the tarasque still lives in the bay. History shows that Halong Bay has been the setting for local naval battles against Vietnam's coastal neighbors. On three occasions in the labyrinth of channels in Bach Dang river near the islands the Vietnamese army stopped the Chinese from landing. In 1288 General Tran Hung Dao stopped Mongol ships from sailing up the nearby Bach Dang River by placing steel-tipped wooden stakes at high tide, sinking the Mongol Dubhai Khan's fleet. During the Vietnam War, many of the channels between the islands were heavily mined by the navy of the United States, some of which pose a threat to shipping to this day. On October 8th, 2006 it was featured on the Amazing Race 10. The surrounding land region of Halong City is rich with high grade coal deposits (anthracite), and is operated by the Vietnamese government.

Etymology
Local legend has it that long ago, when the Vietnamese were fighting Chinese invaders, the gods sent a family of dragons to help defend the land. This family of dragons began spitting out jewels and jade. These jewels turned into the islands and islets dotting the bay, linking together to form a great wall against the invaders. The people kept their land safe and formed what later became the country of Vietnam. After that, dragons were interested in peaceful sightseeing of the Earth and decided to live here then. The place where Mother Dragon flew down was named Hạ Long, the place where the dragon children attended upon their mother was called Bái Tử Long island (Bái: attend upon, Tử: children, Long: dragon), and the place where the dragon children wriggled their tails violently was called Bạch Long Vỹ island (Bạch: white- colour of the foam made when Children Dragon wriggle, Long: dragon, Vỹ: tail).

Geographical Location
Ha Long Bay is in northeastern Vietnam, from E106°56' to E107°37' and from N20°43' to N21°09'. The bay stretches from Yên Hưng district, past Hạ Long city, Cẩm Phả town to Vân Đồn district, bordered on the south and southeast by the Gulf of Tonkin, on the north by China and on the west and southwest by Cát Bà island. The bay has a 120 kilometre long coastline and is approximately 1,553 square kilometres in size with about 2000 islets. The area designated by UNESCO as the World Natural Heritage Site includes 434 km² with 775 islets, of which the core zone is delimited by 69 points: Đầu Gỗ island on the west, Ba Hầm lake on the south and Cống Tây island on the east. The protected area is from the Cái Dăm petrol store to Quang Hanh commune, Cẩm Phả town and the surrounding giants zone.

Climate
The bay is a sea islands in tropical wet with 2 seasons: hot and moist summer, dry and cold winter. Average temperature is from 15°C- 25°C. Annual rainfall is between 2000mm and 2200mm. Ha Long Bay has the typical diurnal tide system (tide amplitude ranges from 3.5-4m). The salinity is from 31 to 34.5MT in dry season and lower in rainy season.
 
System of isles and caves
The bay consists of a dense cluster of 1,969 limestone monolithic islands, each topped with thick jungle vegetation, which rise spectacularly from the ocean. Several of the islands are hollow, with enormous caves. Hang Đầu Gỗ (Wooden stakes Cave) is the largest grotto in the Ha Long area. French tourists visited in the late 19th century, and named the cave Grotte des Merveilles. Its three large chambers contain large numerous stalactites and stalagmites (as well as 19th century French graffiti). There are two bigger islands, Tuần Châu and Cat Ba, that have permanent inhabitants. Both of them have tourist facilities, including hotels and beaches. There are a number of wonderful beaches on the smaller islands.
Some of the islands support floating villages of fishermen, who ply the shallow waters for 200 species of fish and 450 different kinds of mollusks. Many of the islands have acquired their names as a result of interpretation of their unusual shapes: such names include Voi Islet (elephant), Ga Choi Islet (fighting cock), and Mai Nha Islet (roof). 989 of the islands have been given names. Birds and animals including bantams, antelopes, monkeys, and lizards also live on some of the islands.
Almost these islands are individual towers in a classic fenglin landscape which height is from 50m to 100m and height/width ratios up to about 6.
Another specific feature of Halong Bay is the abundance of lakes inside the limestone islands, for example, Dau Be island has six enclosed lakes. All these island lakes occupy drowned dolines within fengcong karst.
 
Inhabitants
A community of around 1600 people live on Ha Long Bay in four fishing villages: Cửa Vạn, Ba Hang, Cống Tàu and Vông Viêng in Hùng Thắng commune, Hạ Long city. They live on floating houses and are sustained by capture fishing and marine aquaculture (cultivating marine biota).