Archaeologists have uncovered a hidden underground chamber beneath Hadrian's Villa in Tivoli, Italy, in a discovery that could reshape historians' understanding of one of ancient Rome's most famous imperial estates. The find was recently announced by Pablo de Olavide University (UPO) in Seville, Spain. Researchers believe the underground structure predates Emperor Hadrian's reign by several centuries, making it potentially the oldest known structure at the historic site.