San Manno Hypogeum - Perugia
The Ipogeo di San Manno is in the locality of Ferro di Cavallo, at a short distance from Perugia. It is in a medieval house, property of the Knights of Malta.
The hypogeum consists of a large rectangular room with a vaulted ceiling and is completely faced with a layer of travertine slabs, perfectly aligned and joined together "a secco", i.e. without the use of mortar.