The history of Palazzo Montecitorio is quite turbulent and began in 1653, when Innocent X commissioned Gian Lorenzo Bernini to build a residence for the noble Ludovisi family. Bernini created a building completely integrated into the pre-existing urban layout.

The palace likely takes its name from "Mons Citarius," as it is believed that the Romans held their electoral assemblies in that same area. The façade of the palace follows the curved line of the facing street and features a flat central body and two lateral wings, each of which is in turn composed of two distinct sections.

Work on the palace was interrupted and resumed only 20 years later due to a dispute between Innocent X and Prince Niccolò Ludovisi (who had married the Pope's niece, Costanza Pamphilj). The work was entrusted to a new architect, Carlo Fontana, who preserved the characteristic convex façade while adding the bell gable and the two doors to the sides of the main entrance. The building became the seat of the Papal Curia.

After the unification of Italy, the palace was intended to house the Chamber of Deputies, so it was necessary to expand the structure. The first project, entrusted to Paolo Comotto, who built a semicircular hall in the courtyard, was a failure to say the least: the hall had been built in the internal courtyard using an iron framework covered with a wooden structure. After some time, it was declared unsafe and closed permanently in 1900.

The expansion of the palace resumed, and the Palermo architect Ernesto Basile, a leading exponent of the Italian Art Nouveau movement, was hired. He preserved Bernini's façade and built the two-story hall. Behind it, a new building featuring four towers. Inside, the current parliamentary chamber was located, illuminated by an extraordinary Art Nouveau fan-shaped skylight, the famous Velarium by Giovanni Beltrami. The large hall, completely furnished in oak, preserves on the ceiling, surrounding the large decorated skylight, a canvas painting by Giulio Aristide Sartorio depicting Italian Civilization and the Virtues of the Italian People.

All the rooms are richly furnished with ancient and modern works of art. Inside, we find the grand staircase and, among the various rooms, the Salone della Lupa, so called because it houses a large reproduction of the Capitoline Wolf: here in 1946, the outcome of the referendum establishing the Republic was proclaimed.

The large corridor that runs alongside the hall is known as the "Transatlantic" for its wooden ceiling, furnishings, and abundant Art Nouveau decorations, reminiscent of the grand salons of early 20th-century ships.

In front of Palazzo Montecitorio stands the obelisk sculpted for Pharaoh Psamtik II (594-589 BC), who is depicted as a reclining sphinx. The 21.79-meter-tall red granite obelisk was originally erected in Heliopolis to commemorate the victories over the Ethiopians. It was transported to Rome by Augustus and erected in 10 BC in the Campus Martius, in the area between the present-day Piazza di Montecitorio and Piazza di San Lorenzo in Lucina, to serve as the indicator arm of an enormous sundial.