Naples Cathedral (Duomo di San Gennaro)

In addition to a precious reliquary ampule said to contain blood of the saint, the site holds important works of art, including frescoes by Domenichino and Giovanni Lanfranco in the Royal Chapel of the Treasure of San Gennaro, paintings by Perugino and Luca Giordano in the main church, and fourth-century mosaics decorating the baptistry. To fully grasp the historic and artistic importance of the Duomo di Napoli, visiting with an expert guide is recommended. Underground archaeology walking tours are an excellent way to explore the catacombs, and a combined tour of the most important churches in Naples—Gesu Nuovo, the Sansevero Chapel, and the duomo—covers the highlights of the city in one day.

• The underground archaeological area is open on weekdays all day, and on Sundays until 2pm.

• Consider a day trip to Naples from the Amalfi Coast or Sorrento if you would rather stay somewhere quieter than the center of this bustling capital city.

• The catacombs are completely accessible to visitors with limited mobility.

• San Gennaro is a Catholic church, so modest attire and appropriate decorum are required to enter.

The cathedral is located in the center of historic Naples on Via Duomo, and can be reached by taking the underground metro to Piazza Cavour.

The region of Campania, especially along the coastline, is very crowded during the summer vacation season. If visiting between June and September, expect large numbers of fellow travelers in Naples.

The cathedral is dedicated to Naples' patron saint, San Gennaro, whose ampule of blood is shown publicly three times a year—the first Saturday in May, September 19, and December 16—for the Miracle of San Gennaro. If the blood liquefies, good fortune will reign in the city. If not, Naples is said to face tough times. (Luckily, it nearly always liquefies.)