This week we look at metals and metallurgy, and this includes the industrial processes that make modern life possible, such as steel and aluminum production. Part of this weeks chapter focuses on the production of steel, which is an alloy of iron with other added elements. In the United States a large amount of the steel production occurs in an area called the "Rust Belt", from northern Illinois, southern Michigan, through northern Ohio, and into western Pennsylvania. Given what you know about the production of steel, why is it concentrated in this area of the country?