History of Dugout Houses

I've gone camping in Texas during the Summer months and it is not a very enjoyable experience.  The heat is incredible and I've a very difficult time sleeping while hot.  As I think about owning property with a cabin, I wonder how I'll manage during the Summer as I'd like to be comfortable year round.  While looking for details on how people in the past managed the Summer months without air conditioning, I stumbled upon dugout houses.

A dug out house is one in which a part or all of a level is underground.  Some of the early examples were quite crude with dirt floors and walls.  However, they certainly have benefit as placing a portion of the home underground reduces interior temperatures.  

The following image is of a dugout house from 1909 in Oklahoma.

This next example is of a house in Pie Town, New Mexico.

Pictures courtesy of Tiny House Blog

More pictures:
1933 Wyoming Dugout
WWII Dugout in Finland (YouTube video)