Godzilla

"Gojira" was a Japanese horror film (it would not be considered a "monster movie" until it reached American shores) that depicted a large radioactive animal (believed by scientist characters to have lived sometime in the intermediate stage between the prehistoric era and current times) that attacks and sinks several fishing vessels and finally ends with his raiding Tokyo twice over the course of a few days, resulting in the city's destruction and wide-scal deaths. His rampage is clearly meant to reflect the atomic bombings of Hiroshima and Nagasaki (though no dirrect political connection is ever made), though most people do not know how the concept for the movie was originally created.