Villa Celimontana is a public park in Rome, on the western summit of the Celio hill, whose creation dates back to the sixteenth century. It was subject to transformation in the landscaped sense in 1858 by the architect Pierre Charles L'Enfant, and again in 1870, with interventions in neo-Gothic style. The Villa covers a site of Flavian and Trajan periods of which are city walls. Archaeological excavations have brought to light in 1889, the Hilariana Basilica, erected by Manius Publicius Hilarus, and its unique mosaics, but the exhibits are numerous and include the famous Egyptian obelisk of Ramses II. The monumental portal was rebuilt in 1931. The driveway leading to the Casino, or Mattei Palace, by Jacopo Del Duca, current headquarters of the Italian Geographic Society.