Vasari Corridor

The Vasari Corridor (Italian: Corridoio Vasariano) is an elevated enclosed passageway in Florence, central Italy, which connects the Palazzo Vecchio with the Palazzo Pitti. Beginning on the south side of the Palazzo Vecchio, it then joins the Uffizi Gallery and leaves on its south side, crossing the Lungarno dei Archibusieri and then following the north bank of the River Arno until it crosses the river at Ponte Vecchio. At the time of construction, the corridor had to be built around the Torre dei Mannelli, using brackets, because the owners of the tower refused to alter it. The corridor covers up part of the façade of the chiesa di Santa Felicita. The corridor then snakes its way over rows of houses in the Oltrarno district, becoming narrower, to finally join the Palazzo Pitti. Most of it is closed to visitors.

The Vasari Corridor was built in 5 months by order of Duke Cosimo I de' Medici in 1565, to the design of Giorgio Vasari. It was commissioned in connection with the marriage of Cosimo's son, Francesco, with Johanna of Austria. The idea of an enclosed passageway was motivated by the Grand Duke's desire to move freely between his residence and the government palace, when, like most monarchs of the period, he felt insecure in public, in his case especially because he had replaced the Republic of Florence. The meat market of Ponte Vecchio was moved to avoid its smell reaching into the passage, its place being taken by the goldsmith shops that still occupy the bridge. At the latter extremity, the corridor was forced to pass around the Mannelli's Tower, after the staunch opposition of that family to its destruction.

...
Wikipedia