What does the thought of an underground house bring to mind? The quaint green mounds from The Hobbit? Or Coober Pedy's pink rock dug-outs?
Well, things in the world of the earth-covered houses have moved on. Today's 'sheltered' homes are sophisticated, light-filled spaces built from sustainable materials, at a comparable price to conventional housing, that keep residents comfortable and - above all - cool.
Not only that, but they present one of the best methods for protecting your home from bushfires.
After the summer from hell, many Australians are prepared to think out of the box for a home that will survive the toughest test of the bush.
Paul Mitchell is one man who has seen this day coming for decades. He has been building bushfire resistant earth-sheltered homes for 35 years through his Adelaide Hills-based company ShelterSpace.
"This is a watershed moment," said Paul, pointing to the thousands of houses lost over the summer. "Now is the time to act. We need to do something different, because clearly, we're not doing it right. All the building codes and legislation plainly don't work as they should."
Enthusiasts for earth-covered homes have in the past been treated by the media as cranks, he said, but in the current climate, the public is becoming more receptive to the idea.
The facts really speak for themselves.
"Ninety per cent of traditional houses are lost (in bushfires) because sparks and embers get into their roof spaces," said Paul. "Many of the rest of them go up because fire or wood smashes through the front window. In an earth-sheltered house, you immediately eliminate the roof space and immediately increase the chances of survival. If you apply bushfire-proof shutters, then you've covered all your bases."
Paul began working with the form since the late 1970s, and now designs earth covered homes all over Australia.
"When I first started doing it, I was experimenting, but now I've refined the techniques to suit the building industry using common building materials," he said.
One of his crucial developments has been the incorporation of a small courtyard at the back of the house that goes all the way up to the roofline. There it is covered in glass louvres, which pull a breeze through the house when they are open.
"I went into one of the houses I'd designed the other day, when it was 47 degrees outside," he said. "Inside, it was 27."
Humans have long recognised the thermal advantages to being underground, making their first homes in caves, well away from temperature extremes and threats such as fire.
In most of mainland Australia, the constant temperature below the surface - which is roughly the average annual temperature above it - is usually ideal for comfortable living.
The houses are generally steel-framed and built of core-filled blockwork or concrete poured in situ. The front, or exposed wall, can be built of anything as long as it meets the building code. Paul makes use of plenty of timber and mud brick as well - it doesn't matter, he says, because the steel beams are holding it up.
Paul runs tours of his homes for interested parties. For more information go to www.shelterspace.com.