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")
Fountain worthy capital of the Christian world. In 1453, he began to rebuild the Acqua Vergine, the ruined Roman aqueduct which had brought clean drinking water to the city from eight miles (13 km) away. He also decided to revive the Roman custom of marking the arrival point of an aqueduct with a "mostra", a grand commemorative fountain. He commissioned the architect Leon Battista Alberti to build a wall fountain where the Trevi Fountain is now located. The aqueduct he restored, with modifications and extensions, eventually supplied water to the Trevi Fountain and the famous baroque fountains in the Piazza del