Read this and answer the question. If the question is unanswerable, say "unanswerable".

Building first evolved out of the dynamics between needs (shelter, security, worship, etc.) and means (available building materials and attendant skills). As human cultures developed and knowledge began to be formalized through oral traditions and practices, building became a craft, and "architecture" is the name given to the most highly formalized and respected versions of that craft.

 What was the least valued type of building craft called?
unanswerable