Where was Skull Island in king kong 2 filmed?

The film Skull Island was shot in the largest landscape cave in Vietnam. The landscape cave "Hansong Cave" in Vietnam is the largest cave in the world.

Han Song Dong, located in Viet Nam's Fengya List National Park, has a cross-sectional area of 262×262 feet (about 80×80 meters) in most areas. Han Song Cave was discovered in a remote jungle in Vietnam. Many scientists believe that Han Song Cave is by far the largest single large-scale natural cave in the world, and it is also the largest cave passage in the world.