>Michael E. Reynolds is an American architect based in New Mexico, known for the design and construction of "earthship" passive solar houses.
Here's a video of himself giving a tour and explaining how it works basically; https://www.youtube.com/watch?v=uZw-_rLMiQg

In Phoenix; https://www.youtube.com/watch?v=fkP19pTOz_k

In New Mexico; https://www.youtube.com/watch?v=KWQW6Vo74ho

In Southern Alberta, Canada; https://www.youtube.com/watch?v=EAvY5JeMz9w

In Ontario; https://www.youtube.com/watch?v=aZ3ZykeQGHg

In Colorado; https://www.youtube.com/watch?v=RM5izEs7KEg

In Montana; https://www.youtube.com/watch?v=BNekutd-6qM

In Adelaide, Australia; https://www.youtube.com/watch?v=V1UjbmksKYI

In Belize; https://www.youtube.com/watch?v=fmWv2qEX83g

I know it's not for everyone, but something about underground houses strikes me as an unexploited possibility...man came out of the caves millennia ago and didn't consider going back and making an improved version until recently