Piazza il Campo. But it's not hard to see why, especially on a sunny bright day.
Antica Osteria da Divo was incredible. We were three levels down in a cellar, and the food and wine was just sublime.
Piazzo del Mercato, where there was a Sunday flea market. Fun to see, but it was more
Piazza il Campo, then we went a few hundred meters out of the town you can have some amazing views looking back into the town.