Hadrian's Villa, also known as Villa Adriana, is indeed a remarkable UNESCO World Heritage Site located near Tivoli, Italy. Constructed around AD 120 by Emperor Hadrian, the villa was a grand retreat from Rome, showcasing over 30 buildings set amidst gardens with fountains and basins. Its architecture, featuring innovative designs and the extensive use of concrete, was so advanced that it influenced Baroque architects centuries later. Today, much of the site remains unexcavated, preserving the mystery and grandeur of ancient Roman opulence.