It might sound awkward, but in Turin there is a post office that’s a spot worth a visit in my opinion.
The Palazzo delle Poste e Telegrafi (Post and Telegraph Building) was built in 1911 to host the central post office of Turin, a function that it still has today.
The architectural project was signed by Mr. Dolza, an engineer working at the municipal office, and it is highly representative of the eclectic decorative style of the second half of the 19th century.
The building experienced major damage by bombings in 1943 during WWII, when part of the roof and the upper floor collapsed, and which were later rebuilt.
The office is organized around the central hall, actually the covered courtyard of the building. The glass and metal rooftop provides a lot of light and is reminiscent of closed galleries like Galleria Subalpina (check the article by Chiara Galleria Subalpina – Hidden in plain sight).
In case you need to send postcards from Turin, this is the right spot. My advice is to buy stamps in a T shop (those who sell cigarettes and bus tickets) to avoid the queues at the post office, then come to the Central Post Office to mail them in one of the many mail boxes outside the building, and while you are here, enter and visit the main hall.