The "Doric" nymphaeum comprised a rectangular room carved into the rock covered by a barrel vault and dated from the mid-first century BC. Perhaps it was part of the Domitian Villa even though today it appears isolated. Its walls are carved with a double set of niches surmounted by a Doric frieze, supported by corbels and topped with an extravagant frame. Under the gable there was the real engine of the waterworks obtained through cascades and waterfalls, canals and ditches. The system was powered by one of the aqueducts that crossed Albano and by a series of tanks and water conduits placed behind the central bottom wall.