Robert Bowling stated on his twitter, "The 1st Content Collection, which includes all SIX of the previous #MW3 DLC drops, releases March 20th for everyone on @Xbox Live!"
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It is unknown how much this collection will cost. This will include the Liberation map, the Piazza map, the Overwatch map, the Black Box map, the Negotiator mission, and the Black Ice mission.

Piazza
Piazza is a multiplayer map for Call of Duty: Modern Warfare 3 set in Italy.
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Liberation:
Liberation, set in Central Park in Manhattan, New York, is a multiplayer map for Call of Duty: Modern Warfare 3, included in Content Pack 1.
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Overwatch:
Overwatch is a multiplayer map for Call of Duty: Modern Warfare 3.
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Black Box:
Black Box is a multiplayer map for Call of Duty: Modern Warfare 3.
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Negotiator:
Negotiator is a Special Ops Mission Mode challenge in Call of Duty: Modern Warfare 3.
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Black Ice:
Black Ice is a Special Ops Mission Mode challenge in Call of Duty: Modern Warfare 3.
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