Of the building renovation works started in Florence during the Grand Duchy of Cosimo I dei Medici the most important was undoubtedly the one started in 1560 in the space south of the square towards the river where Vasari was charged with building the main State Magistracy buildings (hence the name Uffizi).
After demolishing one of the oldest town quarters, Vasari built a monumental u-shaped portico building, a real masterpiece of late-Renaissance period architecture. To avoid the unpleasant effect of a long, monotonous facade, Vasari split it using a recurrent motive that allowed him to elegantly connect the two ends to Palazzo Vecchio and to the Loggia dei Lanzi, along with the happy solution of the arched bridge at the end, overlooking the Arno.
Once most of the building had been completed at considerable expense, Cosimo had Vasari undertake another ambitious project: a raised communication passageway connecting Palazzo Vecchio to Palazzo Pitti, his official residence. This is the famous Vasarian Corridor, a route from Palazzo Vecchio across the Uffizi, along the Arno above a portico, crossing it over Ponte Vecchio and on to Palazzo Pitti and the Boboli gardens.
During the XIX century, following indications left by Vasari, they sculpted 28 marble statues portraying the most important Tuscan personalities and placed them in the pillar niches outside the portico.
On entering this great U-shaped square, you notice that difference between the light and shade of the side porticos and the luminosity of the arches in the background anticipating the river presence. From here, looking in the opposite direction, this simple yet complex architectural plant is a perspective spy-glass towards Piazza della Signoria, including in one single backdrop the façade of Palazzo Vecchio with its statues, the fountain in the center and even the Cathedral cupola.