Step into the magic that lies under the ground in Iglesiente, from the red rocks, blue lakes, bright white stalactites and stalagmites to the sparkling transparency of the crystals. The grottoes of su Mannau, in the territory of Fluminimaggiore, are a Karst complex "sculpted" 540 million years ago, and still "living": the calcareous formations are constantly evolving. The cavern winds into the heart of the earth for 8 kilometres, with two main branches: the left originating from the River Placido, with spectacular tunnels and rooms, and the right branch, larger and almost "horizontal", originating from the River Rapido. The visible part is in the first branch, divided into archaeological and speleological parts.
The archaeological room is a large hypogeum temple used since pre-Nuraghic times: the remains of oil lanterns found here were part of the rites of a water cult. The cave was connected to the nearby Temple of Antas, which can be reached by a path already traced out by the Romans. The speleological part starts with the Central room, which has to be passed using ropes.