A wonderful spot to enjoy a glowing Roman sunset, this piazza – which is dominated by the imposing presidential palace of Palazzo del Quirinale – marks the summit of Quirinal Hill. The central obelisk was moved here from the Mausoleo di Augusto in 1786 and is flanked by 5.5m statues of Castor and Pollux reining in a couple of rearing horses. Catch the weekly changing of the (young and very fidgety) guards on Sunday at 6pm in summer, 4pm the rest of the year.