It is located in front of the Basilica of Santa Maria in Domnica and stands on an area of Roman origin. The surface remains that have come down to us are from the Flavian and Trajan eras, given that at that time the place was the seat of the V Cohort of the Vigiles. In 1889, however, archaeological excavations brought to light the Basilica Hilariana, built by Manius Publicius Hilarus, which has mosaics of great beauty. The discovery tells even more about the importance of the area in the imperial era.
The monumental portal is of great majesty, a 1931 reconstruction of the one coming from Villa Giustiniani Massimo, but the Palazzina Mattei, the work of Jacopo del Duca and today the headquarters of the Italian Geographical Society is the spearhead of the structure. To see the Fontana delle Palme and the Fontana della Conchiglia, which decorate the gardens.
The Egyptian obelisk of Ramses II also belongs to the era of the splendor of ancient Rome, coming from the Temple of the Sun in Heliopolis. Since 1926 it has been owned by the municipality of Rome, which assigned the Palazzetto Mattei to the Italian Geographical Society. It has been a public park since 1928 and is famous, as well as for its beauty, because the famous Villa Celimontana Jazz event takes place there.