Iron+&+steel

 =Iron and steel =

“//the old cast iron buildings died out. I'm not really sure whether the new skyscrapers killed them, or the new esthetics//”

The growth of the civilizations has discovered new technologies throughout their existance. Architecture play a significant roll in this evolution. That's why as societies have created new techinques, technologies and materials, architecture is nourished by them and adapting these new forms it "kills" the predecessor elements of construction. Although it is relevant to say that this "killing"doesn't involve forgetting or stop using them completely. As steel was manufactured and its characteristics were able to solve structural problems it "killed" cast iron. All this is because steel is more strong, elastic, workable and for it high resistance in all stresses. It is of relevance to say that the looks of steel makes it far more attractive than cast iron. That is why the author explains that he wasn't sure if the properties of steel "killed" the other one, or if it was indeed its appearance.