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Marine Places

Ha Long Bay

Ha Long Bay is a distinctive region on the coast of Vietnam, within the Gulf of Tonkin. It consists of a body of water filled with nearly 2,000 islands composed of karst (limestone partially dissolved by rainwater). This landscape, which covers an area of just over 585 square miles (1,500 square km), was created by sea-level rise and flooding of a region with a high concentration of karst towers. Several of the islands are hollow and contain huge caves, and a few have been given distinctive names, such as Ga Choi (“Fighting Cocks”) Island, Man’s Head Island, and the Incense Burner, as a result of their unusual shapes. Most are uninhabited. The Bay’s shallow waters are biologically highly productive and sustain hundreds of species of fish, mollusks, crustaceans, and other invertebrates, including corals. Designated a World Heritage Site in 1998, Ha Long Bay is currently under threat from water pollution as a result of mining activities, environmental degradation from urban development nearby, destruction of mangroves, and the removal of corals from reefs for sale to tourists.

Ha Long Bayzoom image
  • Pacific Ocean West
  • Type Primary coast
  • Formation Chemical dissolution and drowning of limestone formations
  • Extent 75 miles (120 km)
  • Location On the Gulf of Tonkin, east of Hanoi, Northeastern Vietnam
Ha Long Bay habitat mapzoom image