Overlooking Piazza Castello, the section built by Juvarra ("illustration, right") constitutes today a scenographic façade a single bay deep, screening the rear part of the edifice, which has remained unchanged ("illustration, above right"). On the exterior, Juvarra expressed what was intended as a magnificent architectural preamble to an edifice that was never built, as a high-ceilinged "piano nobile" with arch-headed windows, which is linked to a mezzanine above it by a colossal order of pilasters of a Composite order. Each pilaster stands on a sturdy and formal fielded channel-rusticated base against the ashlar masonry of the ground floor. The central three bays are emphasised by the bolder relief offered by full columns attached to the façade, which is returned inward behind them to afford a vast glass-fronted central interior space like a glazed loggia. Their prominence is emphasised by the tall socles on which they stand, carved with trophies of arms in relief. In the flanking triple bays, each central bay is broken slightly forwards, given its window a deeper, more shadowed reveal within the depth of the wall; its two outer giant pilasters overlap the main order as if that continued behind them. On either side the bays' windows are set together within a slightly recessed panel, thus there are three layered planes to the façade. The dentiled cornice supported on bold consoles in the frieze breaks forward over the central columns and subtly over the central bays of the flanking sections as well. A conforming balustrade decorated with vases and statues in white marble surmounts the façade.