Piazza Montecitorio was designed with one main idea in mind: to provide access to the palazzo that shares the same name. Palazzo Montecitorio has been the home of the Italian Parliament since 1871.
Montecitorio might seem a strange name for a zone that should be basically flat as suggested by the Roman name for the area in which it is found: Campus Martius (= the Field of Mars).
The ancient Romans were a little expansive with their use of the word "monte" (mountain), and called their hills "monti". But then, there was a hill here and that hill came from a build up of rubble and detritus after the fall of Rome.
The significance of "citorio" is still uncertain, perhaps coming from "accettatorio" to do with receiving, as with important people.
The best way to enter the piazza is from the south, for from that direction you will see it the way it was designed to be seen, with the obelisk and the central section of the facade of the palazzo. The obelisk was originally constructed for the pharaoh Psammeticus II and set up in Heliopolis in the sixth century BCE. The emperor Augustus had it shipped to Italy in 10 BCE and had it set up as a gnomon (shadow caster) for an enormous sundial he had build a few hundred meters north of the obelisk's present location. We are told that it fell during a fire and it lay buried where it fell until it was rediscovered under a building in Piazza del Parlamento in 1748. It was reconstructed in 1792 with the aid of granite taken from the column of Antoninus to fill the missing parts of the obelisk. Today it stands almost 22 meters high, 29 meters including base and globe surmounting it.
The imposing palazzo was designed by Bernini at the request of Nicolò Ludovisi (1655) who wanted to build the grand edifice for his family and work started but was halted due to uncertainties regarding future finance. In 1664 when Nicolo' died the building was still unfinished. Some of the family had already moved into a section of the unfinished palazzo. Carlo Fontana took over the project at the request of Pope Innocent XII late in the century with the aim of finishing the building but for a different purpose: the Roman Curia, where matters of the church were to be discussed. Fontana, following the design of Bernini fairly closely, finished the palazzo in 1697. The only part he altered considerably was the central section of the facade, while maintaining Bernini's overall conception including the two receding wings that helped make the facade seem less monolithic and more stimulating to the eye. The building, used for papal matters, was known as the Curia Innocentiana until 1870, when it became home for the new Italian parliament.