Rocca Costanza (15th century) - Massive castle built by Costanzo I Sforza; it has a square plan with four cylindrical corner towers and a wide dry moat. Later used as prison. Villa Imperiale of Pesaro (c. 1530) - Suburban palace with gardens designed by Girolamo Genga for Duke Francesco Maria Della Rovere and _his_ duchess Eleanora and built from c. 1530 onwards, stands atop the San Bartolo hill. <sep>, Pronoun: his