Half The World Lives In Earth Made Houses...

Half of the world's population, approximately three billion people on six continents live or work in buildings constructed of earth.
The Musgum, an ethnic group in the far north of Africa's Cameroon, create their tall conical dwellings from compressed sun dried mud.
Called Cases Obos, the profile of the structure is that of a catenary arch, the ideal form to bear a maximum weight with minimum material.
The clever relief pattern on the surface is a built-in scaffolding that can support the human body to allow for maintenance of the structure by the re-application of more mud to the surface.
But I guess you knew all that...