We came back for a visit to San Crisogono in January as my family missed the underground ruins in July that are located under the basilica. The basilica is quite nice but is not in the best of condition. The structure is a little dirty on the front and dark inside.
For 3 euros you can meet an usher between the hours of 4 - 6 pm during the week who will allow you to take a self-guided tour of the ancient ruins underneath the basilica. The entry area for this is all the way to the front of the building to a room on the left side of the alter. There is a small brochure provided that explains what you are looking at. There was a guided tour that arrived as I was leaving so was able to hear more about the ruins as well. Lucky! This place is recommended. read more