What vast Roman palace complex in Tivoli was built by Emperor Hadrian?

The vast Roman palace complex in Tivoli built by Emperor Hadrian is Hadrian’s Villa.

Constructed during Hadrian’s reign in the early second century AD, the villa was far more than a single country house. It was an extensive imperial retreat containing palaces, courtyards, gardens, libraries, baths, temples, theaters, service buildings, and water features. Hadrian used the complex as a residence and administrative setting away from Rome, and its architecture reflected ideas and artistic influences gathered across the Roman Empire.

The site is especially famous for features such as the Canopus, a long reflecting pool named after the Egyptian city, and the Maritime Theatre, a circular island structure surrounded by a moat. Many buildings used marble revetments, sculpture, colored stone, and elaborate architectural decoration.

It is often confused with the Domus Aurea, Nero’s extravagant palace in Rome. Hadrian’s Villa is instead located at Tivoli, roughly east of Rome, and its sprawling layout makes it an archaeological landscape rather than a conventional villa. UNESCO listed it as a World Heritage Site in 1999.