I've taken a bit of an interest in the primary building materials being used in Northern Argentina, and Bolivia.
Most of the buildings are built out of bricks. When I say "most", I mean "pretty much all": expensive hotels, the sketchy hotel we stayed in across the street from the Bolivian Migration office, the Bolivian Migration office, etc. These bricks are actually pretty cool, though. They´re mostly hollow, extruded structural tubes. If you need to create a force bearing structure, you can stack them tubularly through a rebar skeleton and fill them with concrete. They´re pretty versatile, and I´m guessing pretty cheap. In North America, most large buildings are built from wood or concrete. In South America, its bricks.
A lot of structures, mostly awnings and other non-inhabitable structures, are built with prefab structural steel members. These "beams" consist of three thick steel poles held together in a triangular structure with smaller steel poles welded between them in a triangular lattice. They make these things in straight or parabolic sections for shed roofs. They´re pretty versatile, structures seem to go up quickly, and they´re probably cheap to work with. they look pretty cool, too.