Just outside the boundaries of the archeological park of Ostia Antica, lies a real hidden treasure: the so-called Mithraeum Aldobrandini (according to the name of the famous noble family, owner of the area where the mithraeum lies). The cult of Mithras, of ancient origins, was very widespread in Ostia, were at least 19 mithraea can be found. All information about this mithraeum here. Next to the mithraeum, a hospital and a little chapel dedicated to Saint Sebastian built by cardinal Domenico Ginnasi in 1630. All pictures by Stefania Gialdroni.