Since 1871 this has been the Lower House of Italy's parliament, which is why police and barricades sometimes prevent you from getting near its elegantly curving façade. (It's best to check the website: open days can be cancelled for important parliamentary events.) Designed by Bernini in 1650 for Pope Innocent X, much of the building has been greatly altered, but the clock tower, columns and window sills of rough-hewn stone are his originals. In piazza di Montecitorio stands the tenth-century BC obelisk of Psammeticus. It was brought from Heliopolis by Augustus to act as the gnomon (projecting piece) for the emperor's great sundial. As part of a recent refurbishment of the square, a new sundial of sorts was set into the cobblestones.