Few celebrities have suffered as public a breakdown as what Britney Spears went through in early 2007. That February, the pop icon left a Antigua drug rehab center after just one day of treatment and returned to Los Angeles, while being followed by an army of paparazzi. In what's become one of the most stunning moments in her career, she headed into a hair salon and shaved her head with clippers. The images were beamed around the world. For a woman whose career was built upon her looks, it was the boldest of bold moves.