The Church of Santo Stefano Rotondo: This church dates back to the year 468 and, with the rhythmic harmony of the three concentric circular naves, the precious marble columns and the circular form itself, all characteristic of ancient Roman architecture, it would seem that the church is an adaptation of a pagan temple.

The external nave was blocked off in 1450, and at the end of the 16th century, the walls were frescoed with 34 scenes of martyrdom, giving a detailed account of every possible means of torture.
The study of martyrs had an educational purpose: It was part of the psychological preparation of the Jesuits who would go to protestant countries under false names in order to convert the people back to Catholicism. If discovered, they would undergo terrible tortures.