That is seriously cool!  I want one! lol ever since I was a little girl I've wanted to live in the side of a hill (or under a tree or in a tree... Winnie-the-Pooh).  Seriously, what an awesome idea/structure/plan/future.

The Taos region is indeed very beautiful, and these people are fortunate to have found so lovely a location for their project.

(Of course, it is not quite so ideal as it used to be.  The region was fairly well-watered in historical times, at least enough to sustain a moderate population.  But lately it has been drying out -- and apparently more of that is what the future holds in store.)

But even the interesting town of Taos, with Taos Pueblo and the exquisite Millicent Rogers Museum in the north, and the old Mission church of San Francisco de Asis to the south, is not culturally self-sustainable.  And then there are transportation needs.  That sort of thing needs to be taken into account when we assess the "sustainability" of a building.

Chickens deserve our true friendship! So do fish! So do other sentient beings! Let us learn to be kind.

Ingenious use of local circumstances to create a sustainable home, but not a model of sustainability for the rest of us, unless we all want to relocate to a former gravel pit in the southwestern desert.

Life isn't just water and energy. Presumably, they'd need roads to service the area (I saw a Prius!), maintenance of those roads, health services, police and emergency, other amenities, like getting your Prius fixed when it breaks down, movie theaters, etc., some kind of organizational governing system--pretty soon, life starts looking unsustainable again.

The owner in the first video says that humans are "enhancing" the natural environment in a way that "mother nature could never do." It's largely a fantasy. There simply are not enough gravel-pits to go around, and the amount of people on this planet would simply overwhelm this concept.

Still, it is ingenious.