Halong bay vietnams unesco protected jewel in the crown is a stunning archipelago of 1 969 limestone pillars and islets rising up from an opal sea covering almost 2 000 square kilometres there is no doubt that the best way to see its primitive beauty is from the air on hai au aviations seaplane even better is to see it all close up as you land on water for an overnight boat stay on the emeraude classic cruise that is exactly what this 2 days 1 night travel package offers