This behind-the-scenes documentary follows Britney Spears during her "Dream Within A Dream" concert tour in Mexico City. She is about to turn 21 years old, and reflects about her fame and future while preparing to retire for a year.

Have you ever had a dream that felt so real, you couldn't tell the difference between the real world and the dream world? On November 18, 2001, the world's biggest star, Britney Spears, brought her "Dream Within a Dream" Tour to the MGM Grand Garden Arena in legendary Las Vegas. Watch this defining concert, witnessed by millions of fans, as it was broadcast live on HBO.