Palazzo Barberini is still the center attraction on the piazza in Rome. This sloping site was passed down from one cardinal to the next during the 16th century but never got completed until the later part of the century. Three great architects worked to create a harmonious whole and extended the nave of St Peter's to enclose the Villa Sforza within a vast Renaissance block. The design of the Barberini palace soon became a combination of an urban palazzo and a suburban villa with a beautiful semi-enclosed garden.

The design of the Barberini Palace is very intricate. The palazzo is set around a forecourt that is centered on Bernini's grand two-storey hall. This section is backed by an oval salone with an extended wing that dominates the piazza. The piazza, however is on a lower level and, at the rear is a long wing that protects the garden from the piazza below. The main block has three tiers of great arch-headed windows. These are like glistening Venetian arcades that are spectacular to see. On the uppermost floor are Borromini's windows which are set in a false perspective that makes them look much deeper than they actually are. The Barberini Palace will certainly astonish its visitors.