The latter is the most unusual of which few equals exist in this world.
Thepit houses of Matmatain Tunisia come the closest.
Even today, some 40 million people are believed to live in cave houses.
These are located in regions on the edges of the Loess Plateau.
Entrance to these pit houses are usually through a ramp or an underground corridor.
The better caves protrude from the mountain and are reinforced with brick masonry.
These houses are very pleasant to livecool in summers and warm in winters.
A simple one-room cave without plumbing rents for $30 a month.
