The church's exterior gives little indication of the treasures that lie inside, such as the large crucifix, painted in 1550, which is suspended in the middle of the central nave. The numerous paintings on display include a lovely St Catherine (1506) by Giuseppe Alvino, known as Il Sozzo (which literally translates as "The Soak"), the grandiose St Mary of the Angels by Gaspare Bazzano, and the frescoes in the chancel.