Halong Bay
Bay of Descending Dragons, is a UN World Heritage site, and it is one of the top sites to visit in Vietnam. Halong Bay is a four-hour drive east of Hanoi, Vietnam in the Gulf of Tonkin. It is spectacular with almost 2,000 limestone islands that rise like monoliths over the bay. The largest island in the bay is Cat Ba Island and is 87 square miles. There is a hotel on the island where many tours spend the night. In these islands are many caves with at least 20 of them open to visitors. Here is a list of some caves you might want to visit,