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 from the conch shell of the triton. The Piazza Navona became a grand theater of water, with three fountains, built in a line on the site of the Stadium of Domitian. The fountains at either end are by Giacomo della Porta; the Neptune fountain to the north, (1572) shows the God of the Sea spearing an octopus, surrounded by tritons, sea horses and mermaids. At the southern end is Il Moro, possibly also a figure of Neptune riding a fish in a conch shell. In the center is the Fontana dei Quattro Fiumi, (The Fountain of the Four Rivers) (1648–51),