The most well-known cave is Phong Nha Cave, which is a system comprising 14 caves and underground rivers that used to be Cham Buddhist sanctuaries around the 9^th and 10^th centuries. Some inscriptions and altars can still be seen inside. The British Cave Research Association attributed six records to the place: the longest cave, the cave with the highest and largest entrance, the most beautiful underground lake, the most sumptuous stalactites, the longest underground river, and the most beautiful and the largest cave. Light reflects on walls, lakes and rivers, and creates a phantasmagorical atmosphere down there. They used to be called the “Fairy Caves” by the Nguyens and they are now considered as one of the most beautiful cave systems in the world. It is now often referred to as “Wind and Teeth Cave” because of the stalactites and stalagmites inside that look like teeth and because of the wind flowing from the cave. A visit costs around 80.000 VND – about 4 dollars.

Thien Duong “Paradise Cave” is one of the most beautiful cave according to certain explorers from the British Cave Research Association. It specifically features stalactites and stalagmites whose shapes and sizes are very various. Unlike in Phong Nha Cave, there is neither water nor life. The price to pay for a visit is around 120.000 VND (about 6 dollars). Accessible caves are quite easy to reach, and they don’t require a perfect physical shape which is why they are so popular among tourists.

Don’t miss Hang En Cave whose name means “swallow,” close to Hang Son Doong. The cave features three openings. The jungle has taken place within it, along with a river. Accessing it is not really a piece of cake: you will have to trek through the jungle, cross a few rivers and villages, climb some rocks… A good physical condition is obviously required. But the cave is worth the journey: sights are breathtaking. Also, be aware that you may sleep overnight in the cave if you feel like it.

Tien Son Cave is a dry cave. It takes little effort to reach it: 300 stairs to climb before accessing the opening. Nevertheless, the site provides a stunning viewpoint over surrounding rice fields, forests and rivers. The fees are 40.000 VND, i.e. around 2 dollars.

Another interesting cave system is Tu Lan’s, which is located in Tu Lan Valley. It is best-known for its impressive natural architecture comprising Buddha- and fisherman-shaped stalactites and stalagmites. Right in its middle stand three limestone pillars next to which springs a natural underground source. Fossils and human remains have been found within the cave system and have turned the place into an archeological site. In order to explore Tu Lan Cave, visitors will have to trek through remote jungle, climb hills and cross rivers; the path may not be easy but it is worth it.

Phong Na – Ke Bang National Park also features the world’s largest cave, known as Hang Son Doong, which means “Mountain River Cave.” It was discovered in 1991 by a farmer but not explored before 2009 by the British Cave Research Association. The cave is so big – 5 times bigger than Phong Nha Cave and twice the size of the former world’s biggest cave, – that it houses a massive tropical forest referred to as “Garden of Edam,” very rare cave pearls formed drip by drip over the centuries, and superimposed lakes. The growth of this fauna has been possible thanks to two openings that let light getting in, and to an underground river. Besides, the cave stands as the perfect habitat for monkeys, bats and other wild species. The access to the cave is very restricted and controlled, and tourists have to pay a hefty fee of 3.000 dollars to tour the place. The whole exploration lasts for a week and requires being in a good physical shape.