A simple alloy made mostly from iron and a very small amount of carbon, usually less than two percent. The reduction in the amount of carbon, relative to cast iron, makes a tremendous difference in utility and performance. Steel itself has numerous alloy variances when combined with certain other elements (aluminum, manganese, chromium, etc.). These alloys all play specific and vital roles in modern-day architecture. As necessity is the mother of invention, steel is a necessity to answer the questions posed by other metals limitations. A highly versatile and cooperative metal that is as strong as it is reliable.