Earth building is especially appropriate for many places 
where other forms of building would be impossible or too 
costly. This is especially true of the use of adobe, 
earthbags, rammed earth, cob, etc. As for the earthship 
concept that uses lots of used tires and cemented aluminum 
cans, etc., this may not be as appropriate, because these 
materials may not be so available. It really depends on 
what can be found in the area where the house it is to 
built.