Well, then I saw your twin brother in tv last month. It was a show, maybe Discovery channel, following 4-5 people living off grid. One was living in a cave system in Arkansas. He would dig for minerals to sell for ammo and barter. And just between you and me, he seemed just a bit south on his compass. So be careful my friend, keep your wits about you and watch out for cave-ins. I just hope you will let me come to visit, as I love caves. And for the Romans, they were quite the builders, but didn't seem to do many small scale domes for the masses, until Bucksamus Fullerium came into power...and as they say, the rest is history!
Amended...domes are still fairly rare to run across, but oddly, there are two others very near to Lynchburg, and within an hrs drive, there are 5 others in the area, and of the 8, 3 are concrete monolithic domes, made by American Ingenuity Domes.