Giant robots have thrived in our popular culture for decades, rampaging through our comic books, video games, movies and Queen album covers. Their appearances in fiction are generally pretty easy to explain. After all, what else are you going to use to battle giant monsters (or other giant robots)?
In reality, of course, we simply don't have to contend with rampaging, mutated monsters -- and I cannot stress enough how useless a giant robot would be against a hurricane or meteor.
Yet at least six giant robots do in fact exist -- and we developed each of them with a particular purpose in mind.