Phong Nha-Kẻ Bàng National Park
Phong Nha-Kẻ Bàng National Park is known for having the largest and third-largest caves in the world: Hang Sơn Đoòng and Hang Én. While camping inside Hang Sơn Đoòng cave for several days would be a dream come true, those who are interested are typically placed on a two-year waiting list and must pay at least $3,000. Quảng Bình’s government allowed the tour operator Oxalis to organize expeditions into the cave; visitors who want a cheaper expedition with a shorter waiting list can also book an expedition to Hang Én. The park also has more than 300 other caves, grottoes, rice fields and hundreds of karst mountains. Remember to pack long-sleeved shirts, pants and bug spray for this adventure.