(CNN) — Experts working on the restoration of Emperor Nero's vast palace in Rome have stumbled upon a secret, underground room decorated with panthers, centaurs and a sphinx.

The chamber, brought to light after 2,000 years, is part of the remains of the Domus Aurea (Golden House), the immense palace that Nero built after the fire of 64 AD that devastated Rome.

The figure of a centaur features in the newly-discovered Spinx Room Ufficio Stampa Parco Archeologico Del Colosseo

A team at the Archaeological Park of the Coliseum, which encompasses the palace, came upon the opening to the chamber by chance as they were mounting scaffolding for work on an adjacent room of the complex.

With the help of artificial lighting, they uncovered a vault covered with colorful frescoes, featuring figures such as the god Pan, a centaur, a panther attacking a man with a sword, and a "mute and solitary sphinx," the Archeological Park of the Coliseum said in a statement.

The rich wall decoration also includes depictions of aquatic creatures, tree branches, flowers, birds and garlands.

Alfonsina Russo, director of the Archaeological Park of the Colosseum, said the "Sphinx Room" -- as it has been dubbed by archeologists -- "tells us about the atmosphere from the years of the principality of Nero."

Other images show a man being attacked by a panther Ufficio Stampa Parco Archeologico Del Colosseo

Much of the room is still underground and filled with dirt, but experts said they will not excavate it further for fears for the stability of the complex.