This trip totally lived up to my expectations - I visited the area using Luxury Cruises and found it to be fantastic. The views are outstanding and it is not hard to understand how it got its world heritage status. The islands are made of limestone and rise vertically out of the bay several hundred feet and are covered with tropical rain forest. Fantastic stalagtites and stalagmites and a fresh water pond in the center of the cave with plants growing to the waters edge. it was simply amazing, breathtaking and unforgettable experience. This is a must do tour when you visit the north of Vietnam, we spend one night on a boat cruise and one on an island; what a wonderful experience.