Vacant

Vacant is a multiplayer map available in Call of Duty 4: Modern Warfare and Call of Duty: Modern Warfare 2 in the Resurgence Pack DLC. It is a small map that is set in an abandoned office building. The main building contains various pieces of office equipment, cubicles, and random debris lying around. Attached to the main building is a warehouse, which connects to the main office area. Outside one can find multiple destroyed vehicles, abandoned shipping containers, and a large oil tank. The map plays host to intense close quarter battles, due to most of the map being indoors, with the outdoor areas usually serving as flanking positions.

Tactics

 * Since most of the map is Close quarters combat, shotguns and SMGs are generally favoured, but LMGs and Assault rifles can prove useful in the outdoor sections of the map.
 * A well thrown grenade can take out multiple enemies, due to the closeness of the hallways and the lack of area to escape to. A RPG-7 or Grenade Launcher could be used just as effectively.
 * Woodland Camouflage and Digital Camouflage are the most useful, but Blue Tiger Camouflage can work decently as well.
 * Despite airstrikes seeming near useless, a well placed airstrike can still kill, as there are holes in the roof of the building, most notably the warehouse.

Domination

 * Flag A - At the SAS spawn point, between the shipping containers and the oil tank
 * Flag B - The outdoor area in the middle of the office complex
 * Flag C - At the Spetsnaz spawn point, at the very back of the computer room

Call of Duty 4: Modern Warfare

 * When the player spectates outside the map and look at the sides of the buildings outside, there are weird and kind of disturbing graffiti paintings of cartoon characters. They look a bit like the cartoon band Gorillaz.
 * There is a poster on a wall in one of the rooms depicting a World War II-era female Russian soldier that is strangely wielding an American Thompson, which the Russians never used. This picture may also be seen in the MW2 single-player map, Loose Ends.
 * There is a Truck parked outside of the warehouse with a license plate "R3TARD0"
 * An Intel laptop can be found in the office area.
 * If the player stands still long enough in the office area the sound of a fan clicking can be heard, someone talking somewhere on the map, and footsteps. This is all heard above the action music.
 * The apartment buildings around the right side of the building (outside the map) don't have any collision effects. If a chopper is called in, it is not uncommon for it to go near these apartment buildings and for at least part of it to phase through them.

Call of Duty: Modern Warfare 2

 * This map is confirmed to be in Modern Warfare 2's second map pack: Resurgence Pack.
 * The Modern Warfare 2 version of this map has removed the gate separating the back office (Spetsnaz spawn) and hallway, when playing Demolition. It is perhaps the only map to feature a piece of terrain that is not in every gamemode.
 * The map itself is much brighter, having less of a gloomy feeling, possibly due to the lack of Night Vision Goggles in Modern Warfare 2.