Marvel at the size of Cathedral of Asti. Go to a mass if you can or just wander around and appreciate the serenity.
When you've finished up at this principal church in Asti, why not check out Piazza Alfieri, Riserva Naturale Speciale Valle Andona, and Riserva Regionale Valle Andona? They're close to Cathedral of Asti and also a favorite with tourists.