In its original form, GODZILLA (GOJIRA) was meant as an analogy for the bombings of Hiroshima and Nagasaki, ending Japan's involvement in World War II. The monster was a representation of nuclear holocaust and its aftermath. Director Ishiro Honda was ingenious in his use of the big lizard as a metaphor for his nation's greatest human tragedy.
Before it could be shown in the United States, big changes had to be made, including the addition of actor Raymond Burr as an extraneous character, and to provide voice-over narration. Burr's character would tell us what was "really" going on. Perhaps, distributors were afraid that American audiences were simply too dense to understand Honda's vision. More than likely, they didn't get it themselves!
GODZILLA: KING OF THE MONSTERS was born.
Unfortunately, much of the story's devastating power was lost in the process. Even so, the Americanized version still packs a punch. Honda's idea shines through, and Burr isn't bad in his role, just unnecessary. If this is the only version you've ever seen, then it's advisable to watch the original for some context...