Ha Long bay - bay of the descending dragon

Long ago, in the first age of Vietnam, when folk still believed in fantastic beasts and miracles, there came a threat from the seas to the North. Fleets of invading ships began to fill the horizon. Not knowing how to defeat this fierce threat the emperor Jade called on a mother dragon and her children to help deter the advancing ships.
The dragons began to set the seas ablaze with their fiery breath and to spit precious stones and jade into the emerald waters. These formed into islands which joining together created an impenetrable barrier through which no ships could pass.
Following the defeat of the invaders the dragons fell in love with the beauty of the bejewelled seas they decided to make it their home.

And that is how Ha Long bay was formed.