The yellow on the map shows the crazy layout of the mapped part of the cave. It was originally discovered as three different large caves before they realized it was all one cave!
The model at the bottom shows how the cave actually exists like a giant pile of spaghetti with many levels. The model is just of the black box on the map.
The cave was carved in soft sandstone and limestone by underground rivers.
Most of the cave system is covered by a layer of hard shale through which surface water can't pass.
This leads to a strange thing: most of the caves have no formations. They are just smooth water carved sides and jagged rocks where ceilings caved in.
But in one part of the cave, the shale covering eroded allowing water from the surface to percolate through...
The water dissolved the limestone and redeposited in stalactites, stalagmites, and all manner of beautiful cave formations!