San Martino Museum
The former Carthusian monastery of San Martino, built in 1325 and rebuilt in the 17th century, also houses the Museo Nazionale di San Martino.
The church, where you should also be sure to see the sacristy and treasury, is richly decorated with marble, ceiling frescoes, and paintings from the 17th and 18th centuries.
There are two cloisters, the Chiostro dei Procuratori and the main cloister, which is surrounded by 60 white marble columns.
The monastery makes a good setting for the museum, which contains porcelain, an 18th-century state coach of Charles III's reign, and various historical relics from Naples and southern Italy in the 18th and 19th centuries.