READER BEWARE: This page is a placeholder until I decide if I want to pursue this subject. It is clear that Petra was build to survive one of the world catastrophes at the end of the last world. But by who and which catastrophe must be learned by deeper study.
This video gives a good idea of the extent of this system of caves:
“Lost Ancient Technology Of Jordan: Petra” from the Brien Foerster YouTube channel: (Brien can get a little tiresome, but he is a totally unique source of information)
This National Geographic article says the water supply system could support 30,000 people: