Another interesting possibility! Underground living in Australia,,,,

[VenomJockey]

http://www.bbc.com/travel/story/20191121-australias-subterranean-oasis

Excerpt: "Nothing about the Australian town of Coober Pedy is for the faint of heart – it’s blisteringly hot, located in the country’s remote Outback interior and is usually covered in a thin veil of red dust from local opal mines. But rather than move to a cooler, more hospitable climate, residents have gotten creative, building a subterranean community in old mines and creating everything from dug-out homes to churches. Today, around 60% of Coober Pedy’s 3,500 locals live underground. Coober Pedy’s origins lie underground, too. About 100 years ago, a teenager discovered a piece of opal in the area. From there, miners flocked to the region, and soon enough, the town of Coober Pedy – the world’s largest source for opals – was born. In its heyday in the 1970s and 80s, the town was home to more than 1,000 miners. Today, there are only about 100."

 

[Just Cliff]

I've wanted to do this since I was a teen in the 80's. I saw a story on the opal mines and how when they played out, they were abandoned. As an Adult, I saw a video on Shotcrete and thought that would be even better to spray on the walls and ceiling. That would keep the red dust down.

 

[VenomJockey]

I've wanted to do this since I was a teen in the 80's. I saw a story on the opal mines and how when they played out, they were abandoned. As an Adult, I saw a video on Shotcrete and thought that would be even better to spray on the walls and ceiling. That would keep the red dust down.

Using shotcrete an underground home could be turned into a palace of a home. I like the idea!

 

[Supervisor42]

Using shotcrete an underground home could be turned into a palace of a home. I like the idea!

Horrible conditions above ground, look below.
As far away as Coober Pedy is, it comes home for me.
Years ago my wife had bought a black opal pendant from there. The stone is so magically deep it's astounding.
She quickly acquired the other parts of the set.

"The Mintabie Opal Field located about 250 km (160 mi) north west of Coober Pedy has also produced large quantities of crystal opal and the rarer black opal. Over the years, it has been sold overseas incorrectly as Coober Pedy opal. The black opal is said to be some of the best examples found in Australia.

Funny story: we were traveling in Silverton CO and dropped into a local shop selling white opals (the cloudy ones).
The owner went nuts and was offering anything in the shop to trade her out of them.
Nope.