The tour underground Cagliari is an unusual and exclusive experience: hidden under the layers of the modern town there's a whole world made of caves, crypts and galleries.
Must see is the Tunnel – Shelter of the Salesian School, a long private gallery used during the II World War as a shelter to the school students from the bombings. Today the gallery almost looks a mystic place with its red-bricked arcades, enlightened by soft candle lights.