A boat trip heads from the village of Son Trach to Phong Nha Cave, now part of the Phong Nha-Ke Bang National Park. Extending over an area of 41 ha, the diverse primitive forest is a Unesco world heritage site. The region is home to more than a dozen caverns, but Phuong Nha, whose magical stalactites and stalagmites sculpted by erosion are truly stunning, is undoubtedly one of the most beautiful.