What is the Esa'ala Cave system?

The Esa'ala Cave System is a fictional cave in Papua New Guinea. It was featured in the 2011 movie "Sanctum." The caving scenes in the movie were actually filmed at the Cave of Swallows in central Mexico, while the above-ground scenes were filmed in Australia.

Like the Cave of Swallows, Esa'ala is a pit cave, a naturally occurring subterranean structure made up of steep vertical shafts. The cave as a large mouth that opens into an underground chamber. In both the real cave and the one in the movie, it is necessary to use climbing equipment and rappelling gear to enter and exit the chamber.