Halong Bay (Water Gulf where the dragon land) is an inlet of the western coast of the Gulf of Tonkin in northeastern sea area of Vietnam, including the sea islands of Ha Long City, Cam Pha Town and part of Van Don island district.
 

Is the center of a large area there are many factors at similarities in geology, geomorphology, landscape, climate and culture, with Bai Tu Long Bay northeast of Cat Ba Island and the southwest, Ha Long Bay is limited to an area of about 1.553km ² including 1960 islands, mostly limestone islands, which are the core of the Bay area of 334km ² clustered dense 775 islands. Tectonic history of the limestone geology of the Bay has undergone about 500 million years to the ancient geographical circumstances are very different; and Karst evolution fully experienced over 20 million years with a combination of factors such as thick limestone floors, hot and humid climate and tectonic processes improve the overall slow. The combination of environment, climate, geology, geomorphology, Ha Long Bay has made to become clustered biodiversity of forest ecosystems, including closed moist tropical evergreen rain and marine and coastal ecosystems banks with more sub-ecosystems. 14 plant species endemic and about 60 endemic species of animals  have been detected in thousands of plant and animal populations in the Gulf residents.