Villa Adriana, declared a UNESCO World Heritage Site in 1999, was built between 118 and 138 AD by Emperor Hadrian, in a green and water-rich area near Tivoli, the ancient Tibur. Villa Adriana in Tivoli covered an area of at least one hundred and twenty hectares, including residences, baths, nymphaea, pavilions, and gardens. The various buildings were interconnected, not only by surface paths, but also by a network of underground roads and sidewalks for services. The richness of the decorative apparatus was extraordinary, now dispersed among important museums and collections in Europe, following looting. Currently, the visitable area is about 40 hectares.