In the Apennine hills south of Bologna is the natural (if improbable) grotto called the Grotte di Labante. In the area nearby they used to quarry a type of sedimentary limestone called travertino, and the grotto is formed from this limestone. A spring flows from the nearby Chiesa di San Cristofano through this cave system and gathers in a small, clear pool. That pool sits by one of the cave’s two main entrances, which are linked by a relatively straight passage. 

A number of smaller side branches can be found winding through the travertine.The largest cavern features a high waterfall that sticks out the side of the rock like some kind of snout or trunk covered in moss and lush vegetation. Sections of the floor of this cave are made up of cave pearls, small round pieces of limestone shaped into spheres by the flow of running water.