[Yes, I am truly in real-world issue avoidance mode …]
I love the occasional Wired articles on technology history, and this one is near and dear to my heart … on 11 November 1856, Henry Bessemer received a U.S. patent for his steel production technology. The article also gives appropriate credit to American William Kelly for having created a similar technology slightly earlier. The Bessemer-Kelly steel production technology was a major, major inflection point in economic history; it made economical the large-scale production of consistent-quality steel, which had physical properties that made it extremely useful in a lot of applications where iron was not.
Steel was huge. Today only two of the original Bessemer converters in the U.S. still exist, one of which is installed as a fountain at Station Square in Pittsburgh: