Karst topography is a landscape formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves.
The caves at Sorbas are some of the best preserved and are open for tours of different difficulty depending on the individual. As someone who is a little claustrophobic I’m happy to hear about your adventures and post your pictures here.
There is a web site with details here.