Many of you had the right city: Naples.
Many of you had the right Saint: San Gennaro.
And, a few of you had the right artist: Caravaggio.
One of you had the trifecta, so to speak.
So, well done to you all. I am very impressed.
The mural, from 2016, is the work of a Neapolitan artist, Rosario Bosso (Roxy in the Box). It shows two very important figures in the history of Naples: San Gennaro and Caravaggio. As Andrew mentioned, it can be found in the Piazza Sisto Riario Sforza, near the Duomo.
San Gennaro has the newspaper 24 Ore in his hands. The headlines include “Be quick, work for everyone, tourism and culture” and “Drink Neapolitan”. Caravaggio is reading the New York Times, with a Supersantos soccer ball under his right foot. (Another nod to the culture of Naples.)
You can read more about San Gennaro here San Gennaro
It is notable that the dried blood did NOT liquify in September 2020.