Halong Bay is one of the most famous places in Vietnam and consists of a series of impressive limestone islands that are on the Unesco World Heritage List. There are around 2,000 islands in the bay and many of them have beautiful lush vegetation, making them ideal for walking. Many of the islands are also the home of caves. The best thing to do in Halong Bay is take a cruise, where you can see these islands up close and take trips to caves and floating villages.