(FORTUNE Magazine) – I WAS IN NEVADA GOLD MINING FOR 12 YEARS. When things got slow in the gold market, this sounded interesting, and now I've been doing it for three years. We build big caves for commercial wineries to make their wine, sell, and store it. The biggest was 19,000 square feet and took a year and a half. We also dig personal caves, which are usually about 1,000 square feet. It's a niche market--people want caves for all sorts of things, like dining rooms, movie-screening areas, to hold parties down there.

We generally need some type of hill to build a real cave, and you need to have a decent combination of rock and soil. Sometimes the ground is too hard for our equipment to cut, so we blast it with dynamite, but most of the time we use a large cutting machine. Gravity is really the thing we're overcoming. How fast we go depends on ground conditions. The tunnels are 15 feet wide, and you may be able to advance the tunnel up to 20 feet a day, but occasionally it's as little as three feet. It's pitch-dark in there, so we use construction string lighting. I wear a light on my head, and I can't live without it.

I'll spend around ten hours in the cave a day--I really don't mind being in the dark. It's incredibly gratifying because you're beating Mother Nature and gravity on a minute-by-minute basis. A lot of the personal caves are in cities like L.A. That can be a little tough--everyone wants things tailored to them. Plus, I'm used to being out in the hills. I get claustrophobic in the big cities. Would I ever build a cave for myself? I've always thought that a subterranean or partially subterranean house would be a great thing. I don't know how fancy I'll make it, but it's a great use of space on a hillside. -- Julia Boorstin