When I was very little I lived in a house made of clay, and it was very cute. During my adulthood I have been interested in it, they are materials that come from nature, and together with recycling it is a good idea to help the environment.
I have also seen several documentaries where they create houses with car tires.
I love hearing that you have already lived in an Earthen home. That is really special. I believe the houses made with care tire are called Earth Ships. It is a great way to recycle things that would otherwise go to a garbage lot. There is so much to recycle on Earth so all the creative solutions are needed.