The Tu Lan cave system comprises of more than 20 wet and dry caves, which are thought to be between three and five million years old. Huge caverns, underground rivers and vast dangling stalactites make the caves a big draw for spelunkers (cave enthusiasts) visiting Phong Nha-Ke Bang National Park (although the caves technically lie just outside the park), and the otherworldly landscape even captured the imagination of Hollywood, with Tu Lan featuring as a backdrop in blockbuster Kong: Skull Island (2017).
All trips begin with a countryside hike, past peanut fields and grazing cattle, to the entrance of the cave system, and include a guided tour through at least two caves and a swim in an underground river. Longer tours take in additional caves (both wet and dry) and include nights in campsites nestled in the surrounding countryside, while the four-day iteration offers the chance to abseil inside the cave.