The Albano drain outlet is the most famous among the various ones found in the Alban Hills, and it is also the only one of which something is known through historic sources. According to Livy, it dates back to the beginning of the 4th century B.C., and the Oracle of Delphi, which declared that the city of Veii would not be conquered (by the Romans) unless the Lake Albano was prevented from overflowing its banks. Also Dionysius of Alicarnassus (I,66) mentions Livy’s text, but at the same time suggests that the drain may be older.

The study by Piranesi, full of technical details and beautiful engravings, greatly contributed to its fame. The tunnel is 1,450 m long.

At present the Albano drain is the object of a three-year program of speleological studies (Albanus Project), carried out by Hypogea Federation in cooperation with the Superintendence for the Archeological Heritage of Lazio and the Castelli Romani Park.

A film crew led by Massimo D'Alessandro is following all the investigation of the cavers of the Hypogea Federation, in order to make a documentary on the history and exploration of this ingenious hydraulic work of antiquity.