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The Civ4BuildingInfos file defines all of the game's buildings (city improvements) as well as their effects, like providing extra health and happiness or allowing production of certain units.

All tags must be opened and closed; the first is the "open", the second the "close" tag. If nothing goes inside a "list tag", then it should just be the opening tag with a "/" before the closing bracket. The following tables contain all available tags, as well as their purpose and accepted values.



These tags typically bracket other tags, sometimes the entire file, and are generally used to specify more than one piece of data.

Tag Name Description
BuildingInfos This begins and ends the file. Everything must go in between these two, or it will not work.
BuildingInfo Encloses the entry for each building.


Tag Name Description
Advisor Defines the type of advisor that would recommend this building in the in-game menus.
ArtDefineTag Specifies the tag in the Civ4ArtDefines_Building file that provides graphic data for this building.
Bonus Bonus type that speeds production.
BuildingClass The class of the building, as defined in the Civ4BuildingClassInfos file.
CivicOption Free civics allowed with building (for example, the Pyramids enable all Government civics).
Civilopedia Refers to a tag in the Civ4GameText_Civilopedia_BuildingsProjects file which stores the Civilopedia description for the Building.
ConstructSound Sound used when building is completed. See the AudioDefines, Audio2DScripts, and Audio3DScripts files.
Description Refers to a tag in the Civ4GameTextInfos_Objects file that stores the in-game name of the Building.
FreeBonus Provides the city with iFreeBonus (see below) number of a certain resource, like Hit Musicals (BONUS_DRAMA), Hit Songs (BONUS_MUSIC), or Hit Movies (BONUS_MOVIES).
FreeBuilding Provides the listed building free to every city. For example, the Three Gorges Dam gives a Hydro Station to each city.
FreePromotion Allows building to give listed promotion to all units built in that city, like Red Cross and Medic I.
FreeStartEra Building is free if you start in this Era or later.
GlobalReligionCommerce Earns gold from every city with this religion.
GreatPeopleUnitClass Type of Great Person Points the building generates.
HolyCity If set, the building can only be constructed in the Holy City of the religion specified.
MaxStartEra Latest Era the building can be constructed.
MovieDefineTag Specifies the tag in the Civ4ArtDefines_Movie file that will play when this building is constructed.
NoBonus The building blocks the resource from being accessed in the city. (Ex: National Park blocks coal).
ObsoleteTech Tech that makes the building obsolete (like Economics for Castles).
PowerBonus Any building with this bonus supplies power to the given city (i.e. BONUS_COAL for the Coal Plant).
PrereqBonuses Bonus type required for production.
PrereqReligion Defines Religion needed for production.
ReligionType If set, the Building can only be constructed if the specified Religion type is present in a city within the Civilization (though not necessarily in the city where it is being constructed).
SpecialBuildingType Determines whether or not the building is one the special types listed in the Civ4SpecialBuildingInfos file, like a monastery or cathedral.
StateReligion If set, the Building can only be constructed while the specified Religion type is the Civilization's State Religion.
Strategy Refers to a tag in the Civ4GameText_Strategy file that stores the strategic or usage info on the Building, displayed in mouseover pop-ups.
Type The type of Building (see the Civ4ArtDefines_Building file).
VictoryPrereq Victory type required for construction of the building (i.e. the Diplomacy victory condition must be enabled for the United Nations to be available).
DiploVoteType If one is set, the building will allow diplomatic voting of the votes allowed by that vote type; used by the United Nations and the Apostolic Palace.


All of these tags have a numerical value. Though it sometimes can be negative, it usually is not.

Tag Name Description
iAirlift The distance from city that units can be airlifted.
iAirModifier Damage change from air units.
iAIWeight Importance of building to the AI.
iAllCityDefense % change in defense in all cities (e.g. Chichen Itza increases defenses by 25% ).
iAnarchyModifier % change in anarchy length.
iAreaHappiness Change in happiness in all cities on this continent.
iAreaHealth Change in healthiness in all cities on this continent.
iAreaFreeSpecialist Free specialists allowed in all cities on this continent (e.g. Statue of Liberty grants +1 specialist per city).
iAsset Point value of building for victory score.
iBombardDefense Percent reduction in damage to defense a city can get from bombardment from non-gunpowder units
iCitiesPrereq Requisite number of cities for this building.
iCoastalTradeRoutes Increases the number of trade routes in all coastal cities by this amount.
iConquestProb Percentage chance building will survive if city is captured.
iCost Building cost in hammers.
iDefense % change in this city's defense bonus.
iExperience Experience bonus to units built in this city.
iFoodKept % of food kept after city grows.
iFreeSpecialist Free specialists allowed in this city.
iFreeTechs Number of free techs provided when built.
iGlobalExperience Experience bonus to units built in all cities (e.g. the Pentagon gives +2 XP to all units).
iGlobalFreeSpecialist Free specialists allowed in all cities.
iGlobalGreatPeopleRateModifier % increase of Great Person Points generation rate for civilization.
iGlobalHappiness Change in happiness in all cities.
iGlobalHealth Change in healthiness in all cities.
iGlobalHurryModifier % change in hurry cost in all cities.
iGlobalPopulationChange Change in population globally.
iGlobalSpaceProductionModifier % change in spaceship parts production in all cities.
iGlobalTradeRoutes Change in number of trade routes in all cities.
iGlobalWarWearinessModifier % change in war weariness in all cities.
iGreatPeopleRateChange Integer change in Great Person Points generation (i.e. used for wonders, like the Pyramid's +2 Great Engineer points per turn).
iGreatPeopleRateModifier % increase of Great Person Points generation rate in this city.
iHappiness Change in happiness in this city.
iHealRateChange % change in healing rates.
iHealth Change in healthiness in this city.
iHurryCostModifier Building hurry cost modifier (e.g. a value of 100 makes the building, usually a wonder, twice as expensive to rush via gold or population).
iLevelPrereq Requisite unit level (e.g. a level 6 unit is required for West Point).
iMaintenanceModifier % change in maintenance cost.
iMaxLatitude Maximum distance from equator.
iMilitaryProductionModifier % change in military units' production.
iMinAreaSize Size of adjacent body of water for sea buildings (usually 10).
iMinLatitude Minimum distance from equator.
iNukeModifier Damage change from nukes.
iNukeExplosionRand Chance that a nuclear power plant will randomly blow up, causing a meltdown (default 1 in 1000).
iNumFreeBonuses Connected to the FreeBonus tag, this determines how many of the specified resource to provide. -1 gives 5 of the above bonuses. Any number >= 0 is itself, i.e. 10 here with a BONUS_DRAMA in the FreeBonus tag means 10 Hit Musicals from your city. Anything below -1 shows up as that negative number.
iPower Value used by AI to calculate a player's relative strength (Forge, Heroic Epic, etc. influence this).
iSpaceProductionModifier % change in spaceship parts' production.
iStateReligionHappiness Change in happiness with state religion.
iTeamsPrereq Instances among a team in multiplayer (e.g. the Apostolic Palace and United Nations have the value 3, while most buildings have a value of 0).
iTradeRouteModifier % change in trade routes' yield in this city.
iTradeRoutes Change in number of trade routes in this city.
iWarWearinessModifier % change in war weariness.
iWorkerSpeedModifier % change in worker speed.


All of these can either be 1 (on, or true) or 0 (off, or false). Be careful, as you can wind up with a double-negative, which the game will interpret as "True".

Tag Name Description
bAllowsNukes Allows nukes for all players.
bAreaCleanPower Provides clean power to all cities on same continent (e.g. Three Gorges Dam).
bBorderObstacle If Barbarians can no longer cross the players borders.
bBuildingOnlyHealthy Removes unhealthiness caused by buildings (e.g. used by Recycling Center).
bCapital Sets the Capital City. There can only be one per civilization.
bCenterInCity Appears to locate the building at the center of the city. Buildings with a value of 1 for this tag include Aqueduct, Castle, and Monument.
bDiploVote Allows diplomatic votes (e.g. the United Nations); Vanilla and Warlords version of DiploVoteType
bDirtyPower Power provided is polluting.
bForceTeamVoteEligible Forces team members to vote with you.
bGoldenAge Starts a golden age (e.g. used by Taj Mahal).
bGovernmentCenter Makes the city a center of government (multiple allowed per civilization). Used by the Versailles wonder.
bMapCentering On completion, centers the map.
bNeverCapture Indicates if the building is destroyed when the city is captured.
bNoUnhappiness Removes all unhappiness from the city. Used by the Globe Theatre.
bNoUnhealthyPopulation Removes all unhealthiness from population. Used by the National Park.
bNukeImmune Makes the building immune to nuking.
bPower Provides power.
bPrereqReligion Indicates if a Religion must be present.
bRiver Requires river.
bTeamShare Allows team members to build together.
bWater Requires water.

Lists (Multi-line)

All List tags consist of an opening/closing tag, which is shown here, and then each entry within it is another tag with the same name as the parent tag, minus the "s" (i.e. singular, rather than plural).

Tag Name Description
BonusHappinessChanges This defines the changes in happiness provided by the building if you have the specified resources. The tag BonusHappinessChange, bracketed by BonusHappinessChanges, contains each individual resource and its effect. BonusType defines the type of resource, and iHappinessChange defines the amount of happiness increase.
BonusHealthChanges This defines the changes in healthiness provided by the building if you have the specified resources. The tag BonusHealthChange, bracketed by BonusHealthChanges, contains each individual resource and its effect. BonusType defines the type of resource, and iHealthChange defines the amount of health increase.
BonusProductionModifiers This controls the production bonuses for the building as a result of specified resources. BonusProductionModifier contains each individual resources and its effect, BonusType defines the type of resource, and iProductionModifier is a percentage value defining the change in production (e.g. Walls have a value for BONUS_STONE of 100).
BonusYieldModifiers This defines the bonuses to resources' yields from a building. BonusYieldModifier declares each resource, BonusType defines the type of resource, YieldModifiers brackets the three yield tags, and iYield controls the percentage change in food, hammer, and commerce production in that city.
BuildingClassNeededs This tag defines the buildings in the city that are required for the particular city improvement. BuildingClassNeeded defines the individual building classes, BuildingClassType declares the specific type of building, bNeededInCity is a Boolean tag controlling whether the building is needed in this city, and BuildingInfo brackets the entire building group.
BuildingHappinessChanges Defines which other buildings get happiness when this one is built.
CommerceChangeDoubleTimes Defines how many turns must pass before a given commerce output is doubled. For example, Versailles starts giving 10 Culture per turn, but after 1000 years, begins giving 20 Culture per turn. The three iCommerce tags refer to beakers, gold, and culture per turn.
CommerceChangeOriginalOwners Defines the increases in beakers, gold, culture, and espionage per turn that the building provides, using the iCommerce integer tag. Only the player that builds it gets the specified commerce changes.
CommerceChanges Defines the increases in beakers, gold, culture, and espionage per turn that the building provides, using the iCommerce integer tag.
CommerceFlexibles Allows players to adjust the commerce rate, just like technologies.
CommerceHappinesses This determines the percentage change in tax/research/culture sliders' rates, respectively, that produce happy faces, using the iCommerce tag. This is used for buildings like the Theater and Hippodrome.
CommerceModifiers Percentage change to the commerce production for the entire city (e.g. 25 is 25% increase), using the iCommerce tag. The first tag controls beakers per turn, the second gold per turn, the third culture per turn, and the fourth in espionage per turn.
DomainFreeExperiences This tag defines the experience bonus given to units of a certain type. The DomainFreeExperience tag contains each unit type, DomainType declares whether the unit is a land, sea, or air unit, and iExperience is an integer tag defining how many XP points are given to that unit type.
DomainProductionModifiers This tag defines the production bonus given to units of a certain type. The DomainFreeExperience tag contains each unit type, DomainType declares whether the unit is a land, sea, or air unit, and iProductionModifier defines the percentage bonus given to unit construction for that type.
Flavors Used by the AI to decide what buildings to build based on personality
FreeSpecialistCounts This tag lists the free specialists given to a city by the particular building. The FreeSpecialistCount brackets the info for each specialist type (Spy, Engineer, Merchant, etc.), SpecialistType declares the individual specialist type, and iFreeSpecialistCount controls how many free specialists of that type are granted.
GlobalSeaPlotYieldChanges Change in sea square yield for all cities, using the iYield integer tag.
HotKey Essentially useless. This relies on the Boolean tags bAltDown, bCtrlDown, and bShiftDown.
ObsoleteSafeCommerceChanges Additions to commerce outputs that aren't affected by other changes and the building going obsolete. Used primarily for culture per turn, this relies on the iCommerce integer tag.
PrereqBuildingClasses This specifies the amount of certain building class needed to construct this city improvement. PrereqBuildingClass brackets the info for each building class, BuildingClassType declares the building type, and iNumBuildingNeeded states the number of that building type required.
ProductionTraits This tag contains all the leader traits' production bonuses for the building. For example, Aggressive leaders receive a bonus when building a Barracks. ProductionTrait contains the info for each trait, ProductionTraitType defines the particular trait type, and iProductionTrait declares the percentage bonus to production.
ReligionChanges Similar to HOLY_CITY_INFLUENCE in GlobalDefines.xml, sets the change in religious influence the city has, which is used when determining religion spread. ReligionChange contains the info for each religion, ReligionType indicates the particular religion affecting the building, and iReligionChange is an integer tag used to affect this building.
SeaPlotYieldChanges This defines the change in sea squares' yield, using the iYield integer tag for food, hammers, and commerce output.
RiverPlotYieldChanges This defines the change in river squares' yield, using the iYield integer tag for food, hammers, and commerce output.
SpecialistCounts This list tag controls how many of each type of specialist this building allows (e.g. a Library allows only 2 Scientists). SpecialistCount contains the info for each specialist, SpecialistType declares the specialist type, and iSpecialistCount defines how many of that type are permitted.
SpecialistExtraCommerces Bonus provided to specialists by the building, uses iCommerce tag (e.g. Sistine Chapel provides extra culture per turn to each specialist).
SpecialistYieldChanges This controls the bonuses given to each specialist type by the building in question. SpecialistYieldChange contains all of the tags for each particular specialist: SpecialistType declares the type of specialist (Spy, Engineer, Merchant, etc.) and YieldChanges uses the iYield integer tag to modify Food, Hammers, and Gold per turn output.
StateReligionCommerces Bonus provided by buildings of the state religion, uses iCommerce tag (again used by the Sistine Chapel to increase culture per turn output of religous buildings).
TechTypes This tag lists all technologies that are required to allow construction. Note that you must have all of these techs beforehand (i.e. these are AND techs, not OR techs). The PrereqTech tag is used to bracket each individual prerequisite.
UnitCombatFreeExperiences This controls experience point bonuses to units of a certain combat type (Siege, Mounted, Melee, etc.). UnitCombatFreeExperience groups the information for each unit type, and the iExperience integer tag describes how much free XP to give to that type.
YieldChanges Defines the change in city yield, using iYield. There are three iYield tags: the first is for food per turn change, the second for hammers per turn, and the third for commerce per turn (e.g. the Palace provides 8 free commerce per turn).
YieldModifiers Percentage change to the yields for the entire city (e.g. 25 is 25% increase), using the iYield tag. The first tag controls food per turn, the second hammers per turn, and the third commerce per turn. (e.g the Forge provides 25% more hammers per turn)


These tags are directly related to the rendering of art for the entry.

Tag Name Description
fVisibilityPriority Used to give certain buildings priority when drawing them on the map. Most buildings have a value of 1.0, but the Aqueduct, for example, as a value of 10240000.0 in order to ensure that it is always drawn first.


In the following example of code, please note that there is a specific order of all of the tags. You must list the tags in this order for the game to properly interpret your file.





Audio; Buildings:




Civilizations; Events:
















Italics: Beyond the Sword only