Consecrated in 1638, the engrossing chiesa delle cape di morte (the church of the skulls) sits on two levels. While the upper church boasts fine paintings – namely Luca Giordano's The Death of St Alessio and Massimo Stanzione's Virgin with the Souls of Purgatory – the lower church (only accessible by guided tour) is most famous as a hotspot for the cult-like worship of the anime pezzentelle (poor souls).
Between the 17th and early 19th centuries, the large, nameless grave at the centre of the lower church received the remains of countless locals who could not afford to be buried in the church. Heaving with anonymous bones, the hypogeum became an epicentre for the cult of the anime pezzentelle, in which followers adopted skulls and prayed for souls. It was hoped that once the souls reached heaven, they would offer graces and blessings as gratitude. Up to 60 Masses were held here each day, and on All Souls' Day, queues leading into the underground vault would reach the Duomo, 450m away. Although burials on this site ceased soon after the declaration of the Edict of Saint-Cloud (a Napoleonic order banning burials within the city's borders), the wall shrines remained. The most famous of these belongs to 'Lucia' – a tiara-crowned skull named for a neon sign left at her shrine. According to legend, the skull was that of an 18th-century teenage bride, whose tragic death from tuberculosis saw her become the unofficial protector of young brides. To this day, you will find gifts of jewellery and bridal bouquets at her shrine, left by those who still believe in the cult.
The guided tour also takes in the upper church's sacristy, home to a small but beautiful collection of devotional art and ecclesiastical robes. The church is sometimes used for classical-music concerts – check the website (in Italian) to see what might be in the wings.