On the northeastern side of Mount Nerone, in the Marche's Apennines, is the Cave of Tassare. It is the deepest caves in the Marche and is only accessible from Serravalle di Carda, in the municipality of Piobbico. It can be reached walking through the woods and across a mule track, until you get close to the ridge to be followed for 300 meters in altitude. In the cave there are limestone layers, clearly visible even outdoors; in the final part is a 56 meters well. There are tunnels, beautiful galleries, full of concretions, and small wells. Going downwards you find a lake that must be crossed wearing appropriate equipment;  you eventually reach a rather muddy tunnel that ends in the final room at 386 meters.