How did world get the way it is in 1848

This is a very broad question, but since you tagged it
with "Karl Marx," I will assume that you mean something more like "How would Karl Marx
say the world got to be..."  If that is what you are asking, the answer is that it got
that way through a series of conflicts and
resolutions.

Marx believed that there were certain stages
that all civilizations go through.  He believed that each stage was defined by the
conflict between two types of people.  Those two types of people would come in conflict
and out of the conflict would come a new stage of
civilization.

For example, feudalism was the stage just
before the one Marx thought he was living in.  In feudalism, a capitalist class arises
and fights with the aristocracy.  Out of this conflict comes
capitalism.

So Marx said the world got to be the way it was
by going through these stages.