https://www.bbc.co.uk/news/science-environment-49424036
I visited Made'in Saleh about 4 years ago and can recommend it to anyone with an interest in the Nabateans. The site might not be as extensive as Petra, but has the distinct advantage that one is not sharing the experience with several thousand others. When I went there were possibly 50 other visitors on the whole site.
Also within the same site are the preserved remains of one of the main stations on the Medina Railway. For those with an interest in such things, the railway has been almost entirely dismantled, although the permanent way and many stations remain, some of which have been restored.
Down the road from Made'in Saleh is Al-Ula that has the remains of the original town. Also nearby are some spectacular canyons for exploring in one's 4WD - all very Indiana Jones!
Anyway, I attach a few random photos. Anyone know where I can find a sculptor to carve my effigy on a nearby rock? 8)