Piazza Venezia is not only the topographical centre of Rome but its historical locus as well. It forms the nexus between Rome's various historical periods - joining ancient Rome with the Rome of the Popes. It is hands down the most important piazza in Rome- the Capital of Italy- rendering it Italy's center. It's the piazza of the avant-guard, for it is also where Rome's first gas lights were installed and where the first horse drawn buses ran. The piazza, as you see it today, was finally completed in the early 20th century with the construction of the Vittoriano, the monument to King Victor Emanuel. The piazza's name comes from Palazzo Venezia, originally the modest home of the cardinals attached to the Basilica of San Marco. The building was later transformed in 1440 into the residence of Pope Paul II and St Mark's became the pope's chapel. Its architectural conception follows the principles that govern the relationship between buildings and their surroundings, first propounded by the Renaissance architect Leon Battista Alberti. It is a rectangular block with towers at the corners and a central colonnaded courtyard. Palazzo Venezia was the only alternative residence to the Vatican before the Quirinale Palace was built. In the 18th century, it belonged to the Hapsburgs and in the Napoleonic Age it became the Academy of Fine Arts, presided over by Antonio Canova. In 1924 it was taken over by the state and Mussolini established his headquarters there while he was in power. He occupied the Sala Della Mappamondo, the enormous room constructed in 1466 whose name comes from the map of the world which used to decorate the ceiling, but which, today, has all but disappeared. The Benediction Loggia above the main central entrance is called simply "il balcone" by the Romans and is now inevitably linked with Mussolini's appearances.