The world might seem like a dark and dangerous place at times, but it definitely used to be much darker and much more dangerous. Fortunately, history is littered with clever do-gooders who spent their lives doing their very best to improve others'. Many of their discoveries and inventions are things that we take completely for granted today, and the chances are that you've probably never heard of them, but their legacy lives on in the fact that you are still walking, talking and breathing. Unless you've spent your life living under a rock, there's a very good chance you owe a great big thank you to at least one of the people on this list. These are the heroes that Gotham deserves.