9. "Part of Me"
Released: February 13, 2012
Chart Peak: Number One (One week)
After the Brand-Perry's divorce, this leftover from the original Teenage Dream sessions was neatly retrofitted to illustrate the maturity Perry had achieved through overcoming adversity. And that insistent house beat takes on an unmistakable military feel when you watch the video of a heartbroken Katy determined to Private Benjamin her way through Marine boot camp.