Tourism in Rome (with around 4 million tourists a year, making it the world's 39th most popular tourist destination). Other popular sites include St Peter's Basilica, the Forum Romanum, the Pantheon, the Trevi Fountain, the Spanish Steps, Via Condotti, Via Veneto, the Capitoline Museums, the Villa Borghese gardens, the Villa Giulia, Piazza Navona, the Basilica di Santa Maria Maggiore, the Basilica of St. John Lateran, the Piazza del Popolo, the Castel Sant'Angelo, the Campo de' Fiori, the Quirinal Palace, the Lateran Palace and the Palazzo Barberini, to name a few. Rome can be divided into several districts. The so-called historical center ("centro storico")
Piazza della Rotonda the fountain in the Piazza della Rotonda was authorized on September 25, together with a fountain for Piazza Colonna, and two more for Piazza Navona; the fountain for the Rotonda, completed in 1575, was of a chalice-type design, around 3.5 to 4 meters in height, and fed with the Vergine water through a terracotta conduit. Della Porta designed the fountain, and Leonardo Sormani executed it. Due to the slope of the piazza, the fountain is approached by five steps on the south side, and only two on the north. Under the pontificate of Alexander VII Chigi, projects were set afoot