Marilyn has perhaps the most famous walk of them all. Her shimmy is so iconic that it stands alone as the opening scene from Niagara. If you haven't seen it yet, it is worth watching. It is called the longest walk in cinematic history -- over 116 feet of film, according to a quick Google search.
But how did she make her hips sway in a way that was worth expending that much film on?
Perhaps the answer can be found in her biography Goddess. A couple of stories are repeated that at first glance could appear to be nothing more than publicity and hype. But from everything I have read about Marilyn, I'd wager they are true.