Archaeologists have found a secret, underground room inside Emporer Nero’s palace in Rome.

The archaeologists happened upon a secret chamber “decorated with panthers, centaurs and a delightful sphinx” inside of Nero’s famous Domus Aurea (Golden House) while they were doing restoration work on an adjacent room in the complex, according to the Italian news publication ANSA.

Image zoom ALBERTO PIZZOLI/Getty Images

The secret room, which has been buried for an estimated 2,000 years, is nicknamed the “Sphinx Room,” according to ANSA. It’s just one of many rooms in the massive Domus Aurea, which is part of the archaeological park that also encompasses the Colosseum.

Alessandro D'Alessio, the official for the Domus Aurea, told ANSA that restorers immediately went to work excavating the room, which was covered in frescoes set against white backgrounds with red and gold borders, including one depicting the figure of the god Pan and another with a panther attacking a swordsman. There are also depictions of aquatic creatures “both real and stylized,” leafy garlands, tree branches, flowers, and birds.

Image zoom Courtesy of Parco archeologico del Colosseo

Alfonsina Russo, director of the Archaeological Park of the Colosseum, said the room “tells us about the atmosphere from the years of the principality of Nero,” CNN reported.

Parts of the room still remain underground, and archaeologists will not be attempting to excavate the room much further for fears of structural instability, ANSA reported.