Britney Spears' futuristic videos are a triumph of iconic looks (her sassy turn as a flight attendant in "Toxic") and dramatic choreography (the seductive swerves of "I'm a Slave 4 U"). But it's really the videos where she merges the two that put her pop mastery on full display, such as in “Circus”, which combines killer dance moves and edgy costumes to create a gritty, glamorous carnival.