The Roman Popes had a passetto built leading from their Castel Sant'Angelo apartments to the Vatican. Cosimo I commissioned Giorgio Vasari to design a similar passageway from the Palazzo Vecchio to his Palazzo Pitti residence on the other bank of the river, thus avoiding crowds and bad weather. The architect carried out his mission and built this 1km-long corridor, now difficult to visit, although it contains a veritable art gallery.