Palatino - Criptoportico (Cryptoporticus)

To the north of the House of Livia in Rome are the remains of the Cryptoporticus, a semi-subterranean barrel-vaulted corridor 130m/430ft long which linked the various Imperial palaces (the palace of Tiberius, Livia and Flavians) with one another. Tradition has it that the Emperor Caligula was murdered by conspirators in this corridor in A.D. 41.