Phong Nha-Ke Bang National Park is a UNESCO World Heritage Site located in Quang Binh province, near Nghe An. The park is famous for its stunning karst mountains, underground rivers, and extensive cave systems. One of the most popular attractions in the park is the Phong Nha Cave, which is considered one of the most beautiful caves in the world. Visitors can take a boat tour to explore the cave's magnificent stalactite and stalagmite formations. Another must-visit cave in the park is the Son Doong Cave, the largest known cave in the world. The park also offers opportunities for hiking, wildlife spotting, and zip-lining.