Some info

Domus Aurea, built of concrete and brick. It was built after the great fire of Rome which was in 64 AD.
It was rumored to be encrusted with gold leaf, precious gems and rare shells.

The guide told us that there were no kitchens and no bathrooms. Temporary kitchens were set up in tents outside or food was carried from Palatine Hill where Nero's residence was.
It was used just for show and functions. There are 140 plus rooms in the Domus. It may also not have been finished.

after Nero died, Trajan used the Domus Aurea as a foundation for his baths. He filled the empty chambers in with concrete.