Photo: Mariordo · CC BY-SA 4.0 · via Wikimedia Commons
Mud Flood · Rome, Italy
Domus Aurea
The open question
A palace so well buried that people dropped in through a hole in a hill. How did it get that deep?
On the record
Nero's palace was rediscovered at the end of the 15th century when a young man fell through a cleft in the hillside into painted rooms. Artists were let down on ropes to see them.

