This Week in Photos, Sept 7 - Sept 13, 2012

Pop culture dominates this week in photos: Britney Spears makes her X Factor debut, prisoners dance to "Thriller" in Peru, and Grease comes to life in London.

People take part in a sunset yoga session as the Tribute in Light shines over the Brooklyn Bridge over the East River on the 11-year anniversary of the 9/11 attacks in New York. The Tribute in Light is an art installation near the site of the World Trade Center in remembrance of the 9/11 attacks.