Marxism
Marxists believe that if the working class makes itself the ruling class, and destroys the basis for class society (private property, or what Marx called "Bourgeois Property"), there will be a "classless society."  In a Marxist society, no social classes are in conflict, and there is no government anymore.  The state will no longer be needed. There would be no countries. The world will have no borders. There will be communes around the world.  Workers will organize production of goods and services based on what people need, not based on profits.