Paradise Cave (or Thiên Đường Cave) is located in the Phong Nha-Kẻ Bàng National Park in Central Vietnam. With a length of 31 kilometres it is one of the longest caves in SE Asia region. Only the first kilometre however, has stairs and a boardwalk installed and is open to the general public. For the the very adventurous out there are specialised tours which will take you through the whole cave system over 7 days.
The limestone cave system features massive stalactites and stalagmites formations of incredible beauty. Be prepared for a hot and humid, long steep walk up to the cave entrance, lots of stairs in the cave and back down to the carpark area. Hard work but well worth the effort.