Built in the bassi (working-class abodes) of a noble family's palazzo, this jewel-box theatre looks like a grand Italian opera house in miniature form. While it may only seat 99 derrières, it has all the trimmings: parterre and box seats, impeccable acoustics, a 5x7m stage and an orchestra pit large enough for a piano or quartet. From April to October, the theatre is a stop on the A Porte Aperte walking tour. Alternatively, check the website for upcoming performances, which run year-round.