Palazzo Borghese is a palace in Rome, Italy, the main seat of the Borghese family. It was nicknamed il Cembalo ("the harpsichord") due to its unusual trapezoidal groundplan; its narrowest facade faces the River Tiber. The entrance at the opposite end of the building, the "keyboard" of the cembalo, faces onto the Fontanella di Borghese, with another in a great flanking facade to the Piazza Borghese that is extended by a slightly angled facade leading down Via Borghese towards the river.