I discovered this place on line years ago when I was looking for property in Arkansas. It was for sale at the time for the price one pays for a country house in Surrey, a small one, about 4.5 million dollars.
There is more history to this than on the website. I know it. I wonder if any of my readers do?
Just for the record, I always wanted to live off-grid. In the Midwest, one can find cave houses and off-grids....just a thought for you all to ponder.
This post above is dated, but gives you an idea of more cave houses. Here is a photo of one from a site from Greece. And here is another site in St. Louis, with links to more...
In addition for the heck of it are underground sod houses built with some of the same age-old principles as sod prairie houses, but with a difference. I love this one below.
And, in case one wants to live like a hobbit..yes, there are hobbit holes. This one, pictured above and below, is in Wales and the website is fantastic in telling one how to build such a place.