Its interesting to see the different building techniques used in various places. There is a huge variation between North and South of Europe, reflecting climate differences, and in some places earthquake risks. I am sure the same must apply across the States.
The last two pictures resemble to me methods I've seen in the South of France in a relative's new house. Single hollow block walls with some re-bar and a poured concrete "top" which I was told was an earthquake safeguard. In UK the norm is double,(i.e. cavity) walls with insulation between the layers, making an outside wall 12 inches thick
