Underground

Underground is a large-sized map in Call of Duty: Modern Warfare 3. It takes place in a sub-surface London Underground station.

The factions are the Special Air Service (SAS) and the Spetsnaz.

Overview
Underground is set in a London Underground station. It consists of two main areas, the station itself and some walkways around the tracks. The tracks are covered with demolished trains, which can be climbed on and walked through. The main spawn points are at either end of the map, one at the main road and the other at the station's 'Way Out'. The main station has glass roofs, so air support can still affect players on the inside.

Survival Mode
In Survival Mode, Underground is a Tier 1 map and has the difficulty of Easy. The player(s) start with the Five Seven, two Frag Grenades, two Flash Grenades, a Self Revive, and 250 Armor. The hostiles include Bomb Squads, Attack Dogs, Choppers, and Juggernauts.

Trivia

 * There are several advertisements around the platforms, advertising game shows, local train routes and the Museum of History.
 * The station's name is Middleton.
 * There are newspaper stands on the station platform that include a picture of Robert Bowling and the title "Man with beard invents time travel" this can also be seen in French on the level "Resistance"
 * On the tube maps one can see various Modern Warfare-related names, such as Soap Lane, Juggernaut Station, Spec Ops, IW Central and several others. There is also a station called Nedzman Way, which is similar to name of the building being built on Hardhat, Nedzman Plaza.
 * There are departure boards which show the next trains to leave from the station. The destinations are Preston, Liverpool Lime Street, Milton Keynes Central, Watford Junction, Manchester Piccadilly, and Aberdeen. The trains on the map have none of these destinations however.
 * There are over 13 platforms according to the departure boards but not even 10 can be seen.
 * There is a wall clock on the map that says the time is 10:10, but the station clock time is 5:13:07, and also the first train is meant to leave at 20:25 although there are already trains docked in the station.
 * In the Multiplayer reveal trailer, the two factions fighting are Inner Circle and Delta Force, not the Spetsnaz and S.A.S.
 * If one flies under the map via spectator mode the player can see what appears to be an image of the River Thames.
 * There is a magazine that says "President plays Spec Ops. State of Ward advises America to play Spec Ops".
 * By the magazine stand next to the stairs leading into the central building of the map, there are two stands, each have a small sign on the very top of them that read "SHG Editions D'art". This is a reference to Sledgehammer Games, one of MW3's developers.
 * If the player enters the two double-decker buses via spectator mode, they can find magazines on the floors and seats reading "IW Mutant Buffalo Returns!"
 * The trains out of the map have destination Westminster, and the trains inside the map have destination Middleton.
 * In a stall in the station, there are two different colored packs of sweets (brown and yellow) that resemble M&M's but say "CofD's" a reference to Call of Duty itself.
 * On the Wii version, the glass on the roof is missing.