Agostino Chigi was the richest banker in Renaissance Rome. He built a suburban villa on the Tiber (1506-1510) and hired every major artist alive to fresco it — Raphael painted the Triumph of Galatea (the sea nymph riding a shell-chariot through waves, surrounded by tritons and cherubs). Sodoma painted Alexander the Great's wedding. Peruzzi painted trompe l'oeil perspectives so convincing that the walls appear to open onto Roman landscapes. The villa is now in Trastevere, open to the public for €10, and receives 50 visitors per day. You stand alone in a room with Raphael frescoes that most art historians only see in books. Rome museums →
Loggia di Galatea (ground floor): Raphael's Triumph of Galatea (1514) — the nymph Galatea riding across the sea on a shell pulled by dolphins, her red cloak billowing, Cupids shooting arrows from above. The composition spirals — every figure's movement leads your eye to Galatea's face. Sebastiano del Piombo's Polyphemus (the one-eyed giant watching Galatea from the adjacent wall — Raphael and Sebastiano working in competition on facing walls). Loggia di Psiche (ground floor): Raphael's workshop painted the ceiling (1518-19) — the story of Cupid and Psyche told in 12 panels framed by painted garlands (fruit, flowers, vegetables depicted with botanical precision by Giovanni da Udine). Sala delle Prospettive (upper floor): Peruzzi's masterpiece — the walls painted as a columned loggia opening onto panoramic views of Rome (Trastevere rooftops, the Tiber, ancient monuments). The trompe l'oeil is so convincing that standing in the room, you feel like you're in an open-air pavilion.
Via della Lungara 230 (Trastevere, 10 min walk from Ponte Sisto). €10. Open Mon-Sat 9am-2pm (last entry 1:30pm). CLOSED SUNDAYS and afternoons. Duration: 30-45 min. 50 visitors max per day — rarely a problem (it's that unknown). Combine: Villa Farnesina morning → cross to Palazzo Barberini (Caravaggio Judith, 20 min walk) → aperitivo in Trastevere.