The tale of the "Bay of Descending Dragons", as it is also known, is legendary. According to local legend, a great emerald-spewing dragon was sent to defend Vietnam against foreign invaders. An impenetrable coastal defense was formed from these emeralds, which are now the islands of Halong Bay. The result is a breathtaking sight of thousands of limestone islets rising out of emerald green water in grand clusters. Denoted a World Heritage Site in 1994, Halong Bay's forested slopes and naturally formed grottoes make it one of the most iconic destinations in Asia, and are predominantly accessed by multi-day cruise tours.