The Cryptoporticus is part of the Domus Tiberiana complex and is 130 metres long. It dates from the Neronian age. Lying below the area that was covered in the 16th century by gardens, the Horti Farnesiani, it extends along what must have been one of the sides of the Domus Tiberiana. The underground corridor, illuminated by small windows, has mosaic floors. On the vault of the Cryptocporticus, the stucco ceiling decoration with vegetal elements and cupids is still visible (now a copy: the original is in the Palatine Museum).