Underground Basilica of Porta Maggiore

Basilica sotterranea di Porta Maggiore

Useful Information

Location: Via Prenestina 17, Roma
Open: SEP to JUL 2nd and 4th Sunday 11.
Groups (-20): SEP to JUL 2nd, 3rd, 4th Sunday 10, 12.
Fee: Adults EUR 5.50, Children (0-11) free.
Online: Adults EUR 2.
Groups (-20): Per Group EUR 40, Guide EUR 90.
Classification: SubterraneaCave Church
Light: LightIncandescent Electric Light System
Dimension: Basilica: L=12 m, W=7 m, Ar=120 m².
Vestibule: L=3.6 m, W=3.6 m.
Guided tours: D=60 min. Italiano - Italian English Français - French Deutsch - German Español - Spanish
Photography: allowed
Address: Underground Basilica of Porta Maggiore, Via Prenestina 17, 00182 Roma, Tel: +39-06-3996-7700.
Sovrintendenza, CoopCulture, Tel: +39-06-39967702. E-mail:
Cooperativa Il Sogno, Viale Regina Margherita, 192, 00198 Roma, Tel: +39-06-8530-1758, Fax: +39-06-8530-1756. E-mail:
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.


23-APR-1917 rediscovered by accident.
1951 protected with reinforced concrete.


The Basilica sotterranea di Porta Maggiore (Underground Basilica of Porta Maggiore) has been closed for years while renovation works were executed. The site has now been reopened but only with partial access. It is not possible to enter the basilica, only the viewpoint in the atrium. The number of visitors is restricted to six per tour.

The underground basilica is located under the Rome-Cassino railway line, about 9 meters below the level of the current via Prenestina. It was discovered after a land subsidence caused by the vibrations of the trains. The ongoing vibrations were further damaging the church, and after the occurrence of a water intrusion the church was protected by a massive container of reinforced concrete in 1951.

The structure consists of a dromos, a vestibule and a main basilical hall. The dromos was the original entrance from the Via Prenestina. From the ancient street level a long gallery with a barrel vault descended with a steep slope to the vestibule. It is located on the northern side of the basilica. Most of this corridor is destroyed, only the lower part remains. The vestibule is a quadrangular room, 3.6 m wide, with a pavilion vault perforated by a skylight. The main basilica chamber is 12 m long and 9 m wide and divided by six pillars into three naves, each covered with a barrel vault. At the wider central nave end in a semicircular apse.

The basilica is decorated with a mosaic floor, stucco and frescos showing scenes of the classical mythology, mystical rituals, or scenes of everyday life. The apse contains a basin showing Sappho launching from the cliff of Lefkáda. Then there is Ganymede kidnapped by Zeus in the form of an eagle. And the abduction of one of Leucippus’ daughters. Then there are images of vases, candelabras, and musical instruments. Large panels on the wall depict a stylized landscape.

The basilica was located immediately outside the Porta Maggiore, one of the city-gates of Imperial Rome. It was also the junction of several important aquaeducts of the city. The basilica was named after this place. There are various hypotheses on its use, one guesses, it was a neo-Pythagorean sanctuary destroyed under the emperor Claudius. Or it was a funeral basilica from the late Augustan or Tiberian era. However, it was constructed and probably lost during the 1st century.