Ha Long Bay, in the Gulf of Tonkin, includes some 1,600 islands and islets, form­ing a spec­tac­u­lar seascape of lime­stone pil­lars. Because of their pre­cip­i­tous nature, most of the islands are unin­hab­it­ed and unaf­fect­ed by a human pres­ence. The site‘s out­stand­ing scenic beau­ty is com­ple­ment­ed by its great bio­log­i­cal inter­est.