Actually, my friend @roswelborges it is an opera house, but yes, I can see why you connected it with a church, in the photo I chose as the cover photo for this blog, it really does look like one. 🥰
We didn't go inside, we just admired this beauty from the outside and took some photos in front of it.

By the way, one interesting fact, they say that when it comes to filming in Sicily, the exterior scenes are usually filmed in Palermo because of its beautiful facades, while the interiors are mostly filmed in Catania because they have incredible interiors. 😍