Cave House, Festus, USA from Top Cave Houses
This contemporary energy-saving house covers 1.300 m2. It was built in the state Missouri by Curt and Deborah Sleeper. The interior is modern. Thanks to the geothermal heating there is no need for any other kind of heating and cooling system. This space used to be a place where concerts had been held, before it was bought and redecorated by the mentioned couple.