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This article has been verified for the current console version (2.2) of the game.
Note: Ringworlds can be restored even without Utopia enabled.
Humanoid Empire constructing a Dyson Sphere

Megastructures are colossal constructions. Expensive and time-consuming to build or repair, these remarkable feats of engineering are nonetheless important wonders that provide large bonuses, demonstrating the technological and economic primacy of the builders' empire. All of them require unlocking certain technologies or perks to be built.



There are three types of megastructures: gateways, habitable projects and galactic wonders. Systems can only host one megastructure (Unless its a habitat), except for gateways, which can be built in systems where there is already a megastructure. Habitable megastructures (habitats and ringworlds) can be colonized but will be irreparably destroyed if a crisis overruns them. Galactic wonders provide massive bonuses and cannot be destroyed by any crisis, but are limited to one per empire. All megastructures have a different textures depending on the empire that built them.

It is only possible to build, upgrade, or restore one megastructure at a time, except in the case of habitats and gateways.

A construction ship is required to build the first stage of any megastructure. If the megastructure has multiple stages, the following stages do not require the construction ship.

Unlocking new megastructuresEdit

Except for gateways, ascension perks are required to unlock the ability to build new megastructures. An empire that conquers a system with a megastructure can use it, but if the construction was partial, it will not be able to continue its construction without the required ascension perk. Damaged megastructures found through exploration, however, can be reconstructed by unlocking the   Mega Engineering technology. The following ascension perks allow for the construction of megastructures:

  Ascension perk Technology requirements Unlocks
  Voidborne   Star Fortress
  Galactic Wonders   Mega-Engineering


A few bonuses affect megastructure construction speed. These are highly desirable considering the great time requirements of such projects:

  •   Master Builders ascension perk increases the build speed by +50%
  •   Living Metal Mega-Construction edict increases the build speed by +50%
  •   Architectural Renaissance unity ambition also increases the build speed by +50%


Real scale of a Gateway

While exploring the galaxy, empires can find abandoned gateways that were once part of a massive, galaxy-spanning network. Reverse-engineered from encountered abandoned gateways, these megastructures require the   Gateway Activation technology and can be used to travel directly to any other active gateway in the galaxy. Reactivation of gateway takes 2 years and costs 6 000   energy and 2 500   alloys. The   Gateway Activation technology can appear as a research option as soon as a Gateway has been discovered but the chance is very low. Owning a system with an inactive Gateway increases the chance for the tech to appear by 4 time.

When the first gateway in the galaxy is re-activated, another random gateway will also be re-activated along with it. As opposed to wormholes, both gateways must be owned by the same empire or two empires with open borders in order to be able to travel through them. Systems with gateways count as bordering for the purposes of diplomacy, so every opened gate increases diplomatic tension between all active gate-owners. Claims cannot be extended through gateways. Additionally, gateways are able to greatly enhance and simplify trade infrastructure.

Eventually, empires can build their own gateways by researching the   Gateway Construction technology. Notice, that this tech requires having some civilization with an access to pre-existing gateways, so if gateways were disabled during galaxy creation it is impossible to build any new. Each system can have only one gateway, but black hole systems with an L-Gate can also have a regular gateway constructed. Gateways can be built in systems in which there is already a megastructure. The construction site is built in only 3 years and costs 100   influence and 2 500   alloys. Upgrading it to a gateway takes 5 years and costs 6 000   energy and 2 500   alloys.

Habitable megastructuresEdit


Mammalian habitat.

Artificial planets in all but name, habitats have a   planet size of 6 (unless the owner has the   Master Builders ascension perk, in which case the habitat will have a planet size of 8 ) to work coupled with 100%   habitability for all species. Its appearance is dependent on the builders' empire appearance. The constructed habitat still requires colonization.

Habitats have a unique set of districts distinct from normal planetary ones.

The project takes 5 years to complete and costs a total of 200   influence and 3 000   alloys. Unlike other megastructures, habitats do not require a construction site and are finished in one go by the construction ship.

Habitats require the   Voidborne ascension perk to be built. They cannot be built on moons or planets with an anomaly.

If a habitat is destroyed by a crisis or World Cracker it will never be possible to build another habitat on the same spot, or even a mining/research station, so any   strategic resources on the planet are permanently lost.


Finished Ring world.

Immense in both radius and scope, ringworlds encircle their system's star and award their owner four ringworld sections when fully constructed. The carefully designed ecosystems and finely-tuned atmospheres of their sections offer perfect living conditions towards all residing species, granting inhabitants 100%   habitability on the ring world's surface.

Ringworlds do not have planetary features like regular planets, and their planet art resembles that of   Gaia worlds. Unlike habitats, they use the normal building and district set. Ringworlds are limited to City, Agriculture and Generator Planetary Districts, with a limit of 50 per section for a total of 200 per completed ringworld.

The project takes 58.33 years to complete and costs a total of 300   influence and 55 000   alloys. With the   Master Builder ascension perk it takes 38.88 years instead. However, because each section is built separately after the completion of the frame, the Ringworld can be a valuable and productive asset long before its completion.

The initial site is built by a construction ship around the star, and cannot be begun if another construction ship is building a megastructure or if the system contains habitable planets. Once the site is complete, the subsequent sections built without the need for a construction ship.

Ringworlds cannot be built around black holes or in systems with multiple stars. All planets in the system are consumed upon the completion of the frame. As habitable sections of the ringworld are completed, additional, uninhabitable sections will also appear in the spaces between them. These serve little purpose except if the ringworld is built in the L-Cluster, in which case they can be mined for the unique Strategic Resources present in the cluster.

Building ringworlds requires the   Galactic Wonders ascension perk. The following list shows the upgrade order:

Stage Upkeep Time Cost
  Site   -5   5 years
  3.33 years
  5 000
  Frame None   13.3 years
  8.88 years
  10 000
  Completed Section (x4) None   10 years
  6.66 years
  10 000
  Total Cost None   58.33 years
  38.88 years
  800 (site upkeep)
  55 000

Construction EventsEdit

The following events can take place while constructing a ringworld:

  • Favorable leadership conditions increase the building speed by 20%.
  • A mineral deposit is discovered and you are given the option to halt construction for 20 days to get 500   alloys or proceed with the schedule.
  • A number of workers might go missing, delaying the construction for a month. Two months later it will be revealed that one of the planets used in the construction had a species of furry worms the workers have grown fond of. You are given the option to either exterminate them and delay construction for a month or allow them on the building site. Whatever choice is made a month later the worms will be found feeding on the missing workers underground and be exterminated.
  • Another empire might contact you, thinking that you are making weapons of mass destruction on your ring world. They will want to inspect the ring world. If you accept the request the construction will be halted and the empire gets the Request accepted opinion modifier (+40   opinion, -2 yearly). If you declined they get the Request refused modifier, with a penalty of -40   opinion.
  • Another empire can contact you, asking you to allow them to base a group of researchers on your ringworld. If accepted, no time delay will occur, and after a period of time has elapsed (approx. 31 days from acceptance) you will receive 250 engineering points. The empire asking will be a fanatic egalitarian and may be on any diplomatic relation level with your empire. There is a Request accepted opinion modifier (+40   opinion, -2 yearly).

Conquerable RingworldsEdit

Up to 7 ringworlds can spawn naturally in a game in various states. Damaged segments can be repaired with the   mega-engineering tech for the same cost as finishing a new segment.

  • 1 in the Sanctuary system. All 4 habitable sections are intact and each contains one pre-FTL civilization, none advanced beyond Steam Age. The system was abandoned by an Enigmatic Observer Fallen Empire but contains automated defense platforms totaling over 50k fleet power.
  • 3 in the systems of the Ancient Caretakers. The ringworld in the home system has 3 intact and one ruined section while the other two ringworlds are completely ruined and require each section to be repaired separately.
  • 1 in the Cybrex Alpha system. It requires completing the Cybrex precursor event chain. The ringworld is completely ruined and requires repairs on each section.
  • 1 in the Cybrex Beta system. It will only be revealed if the Contingency sterilizes 20% of the galaxy. A short time after the Contingency is defeated, the Cybrex will leave the galaxy, leaving the ringworld free for the taking.
  • 1 in a random empty system if   Utopia DLC is activated. It is completely ruined and each section requires repairing.


Given sufficient resources to construct them, habitats allow even a compact empire to rapidly grow its population, as any number of habitats may be constructed at a time, they can be constructed around a wide variety of celestial bodies, and their buildings are relatively quick to set up. Since research and unity penalties scale towards empire sprawl rather than number of colonies, they are highly efficient for tall empires, as Habitat districts provide a larger amount of housing and jobs compared to regular planet districts.   Gestalt Consciousness empires can build housing buildings on habitat, further improve its performance.

Ringworlds cost 45% less   alloys per district than habitats (275 for ringworlds vs 500 habitats), but 95.5% less   influence (1.5 for ringworlds vs 33.33 for habitats). This calculation changes slightly with the   Master Builders ascension perk due to the increased size of habitats (from 6 to 8 districts). In this case, Ringworlds cost 27% less   alloys per district than habitats (275 for ringworld vs. 375 habitat), and 94% less   influence (1.5 for ringworld vs. 25 for habitats).

Ringworlds can only be constructed one at a time, and their superlative size greatly increases the empire sprawl, but it serves as an ideal place for mass-producing   Energy Credits and   Food since ringworld section has no deposit limit. Since they consume all planets in their system when built (other than the star), it is generally recommended to construct them in systems that are poor in natural resources. If an empire has no   influence banked and earns 5   influence per month, it will take 1 200   days to earn enough influence to build a habitat which is the same amount of time it takes to build the habitat with the   Master Builders ascension perk. Under the same conditions, a ring world may be started every 1 800   days, but allows for a construction that takes 21 000   days (or 14 000   days with the   Master Builders ascension perk) and only one section can be built at a time. This means that for maximum expansion speed, one should alternate the construction of ringworlds with that of habitats.

Both Ringworlds and Habitats are excellent expansion choices for a   Life-Seeded empire.

Galactic wondersEdit

These megastructures require the   Galactic Wonders ascension perk and each can only be built once per empire. However their bonuses are massive and they cannot be destroyed, only captured. Habitats can also be built in the same system as Galactic Wonders. Galactic Wonders cannot be built if there is an existing orbital station (mining/research station), however they can be built around secondary and tertiary stars in multi-star systems. Each Galactic Wonder starts with a construction site that provides no benefit, however each subsequent construction phase will bring increasing bonuses, culminating with the end of the megastructure construction.

Galactic Wonders conquered from other empires do not count against the build limit, nor do ruined ones that are found and repaired.

Galactic Wonder Production Upkeep Time Cost Notes
Dyson Sphere
Site None   -5   5 years
  3.33 years
  5 000
  • Can only be constructed around regular stars
  • Cannot be built if there are habitable planets, anomalies, mining or research stations present
  • Upon completion all rocky planets and moons in the system turn into frozen or cold barren worlds
  • Habitats will be unable to construct solar power processors
Stage I (Frame) None None   10 years
  6.66 years
  10 000
Stage II (Partial 25%)   +250 Energy None   10 years
  6.66 years
  10 000
Stage III (Partial 50%)   +500 Energy None   10 years
  6.66 years
  10 000
Stage IV (Partial 75%)   +750 Energy None   10 years
  6.66 years
  10 000
Stage V (Completed)   +1000 Energy None   10 years
  6.66 years
  10 000
Science Nexus
Site None   -25   5 years
  3.33 years
  5 000
  • The final stage of a Science Nexus can be upgraded to produce 50 more   Research through an event that has a 30% chance to trigger a short time after the Megastructure is finished
Stage I (Hub)   +100 Research
  +5% Research Speed
  -50   10 years
  6.66 years
  15 000
Stage II (Research Wings)   +200 Research
  +10% Research Speed
  -75   10 years
  6.66 years
  15 000
Stage III (Completed)   +300 Research
  +15% Research Speed
  -100   10 years
  6.66 years
  15 000
Sentry Array
Site None   -20   5 years
  3.33 years
  5 000
  • Until finished the Sentry Array cannot see through nebulae
Stage I (Sentry Hub)   +20 Hyperlane Scanner Range   -40   5 years
  3.33 years
  10 000
Stage II (Sentry Spire)   +40 Hyperlane Scanner Range   -60   5 years
  3.33 years
  10 000
Stage III (Sentry Aerials)   +60 Hyperlane Scanner Range   -80   5 years
  3.33 years
  10 000
Stage IV (Completed)   Entire Galaxy Hyperlane Scanner Range   -100   5 years
  3.33 years
  10 000

Ruined Galactic WondersEdit

Ruined Dyson Sphere

A ruined version of a Galactic Wonder can be found while exploring the galaxy, with the largest galaxies having a chance to spawn two or even all three ruined Galactic Wonders. Repairing them only requires the   mega-engineering technology and no ascension perks. If not yet researched, running into a ruined Galactic Wonder also grants a better chance for   mega-engineering to appear as a researchable technology.

While they upgrade from their broken to a fully functional state in one step, they do not count for any achievements. However, they do not count against any build limit for that particular megastructure either. Another megastructure may also be constructed in the same system as a ruined or restored one.

Ruined Megastructure   Time   Alloys
Dyson Sphere 7200 20000
Science Nexus 4800 15000
Sentry Array 4800 15000
Matter Decompressor 4800 20000
Mega Art Installation 4800 15000
Strategic Coordination Center 4800 15000
Interstellar Assembly 3600 20000