Phong Nha
A cave in Phong Nha-Kẻ Bàng. Photo via Wikimedia Commons.
Small town on the edge of Phong Nha-Ke Bang National Park, named for its famous cave. Paradise Cave and Phong Nha Cave are both reached from here by road and river. The town has grown into the adventure hub of the cave region, with farmstays and easy treks.