The headliner in Naples is its historic center (centro storico), which you can visit on foot by strolling the length of Via dei Tribunali and Spaccanapoli, as well as their many cross streets. This is where the famed Sansevero Chapel (Cappella Sansevero) is located, home to the astounding Veiled Christ statue (Cristo Velato) by Giuseppe Sanmartino.
You can also access Naples Underground (Napoli Sotterranea) and the Galleria Borbonica from the historic center, an ancient warren of tunnels that run under the modern city and house a number of Greek and Roman archaeological treasures. Be sure to visit the baroque Duomo, Naples' main cathedral dedicated to the city's patron saint of San Gennaro (and where the legendary ampoule of the saint's blood and the breathtaking Tesoro di San Gennaro are located), as well as the Monastery of Santa Chiara and its beautiful majolica-tiled cloister, and the churches of Gesù Nuovo and San Domenico. In Piazza del Plebiscito, you can tour the Royal Palace (Palazzo Reale) and the San Carlo Opera House (Teatro San Carlo). You'll also want to take a walks down Via San Gregorio Armeno, the picturesque lane lined by artisan workshops that make traditional Neapolitan nativity scenes. Art lovers should pop into the 17th-century Pio Monte della Misericordia to admire works by Caravaggio.
Take the funicular to the Vomero hilltop, where the Charterhouse of San Martino (home to the 19th-century National Museum of San Martino) and Castel Sant'Elmo loom above the city, both full of important works of art and offering sweeping views across the city and bay.
Make time to walk along the waterfront promenade of Via Caracciolo between Castel dell'Ovo and the Maschio Angioino (or Castel Nuovo) to admire the views and rub elbows with locals.
The city's top museums include the National Archaeological Museum (Museo Archeologico Nazionale), home of the Farnese collection, archaeological artifacts and frescoes unearthed in Pompeii, and an impressive Egyptian collection; the Capodimonte Museum with fine collection of paintings, and Madre, dedicated to contemporary art.