Structures

The workhorse of anti-air defense and spy detection.

• Cost: $500
• Strength: 100, Armor: 4, Upkeep: $25
• Fire range: 2 sectors, Fire power: 70
• Built by: Construction Truck (placement on any owned land sector).
• Research: Infrastructure track, position 3.

What Turrets do

• Intercept air units at 100% effectiveness. When enemy Jets, Missiles, Warheads, Spy Planes, Helicopters, or Paratroopers fly through a sector within 2 hops of a Turret, the Turret fires on them (with distance falloff). A single Turret can deal substantial damage to a passing plane. Two Turrets on a flight path can shoot down most air units outright.
• Detect Spies and Submarines automatically. Any enemy Spy within 1 hop of a Turret is detected (the Turret's country gains intel on it), and a Spy that tries to enter the Turret's own sector is captured and destroyed. Similarly, an enemy Submarine within 1 hop of a coastal Turret is exposed (revealed but not killed).

Where to place them

• Around your capital. Nuke deterrence — any approach to your capital runs through turret coverage.
• Around your Air Bases and Sea Bases. Protects your production infrastructure.
• Covering your Refineries. Refineries are high-value income targets; Turrets force the enemy to commit Missiles (expensive) rather than cheap Jets.
• On chokepoints along invasion routes. A Turret line along a mountain pass makes air support over that front prohibitively expensive.

Up to 3 Turrets per sector can be placed, letting you stack defenses on a particularly critical location.

Turrets can be repaired when damaged and sold for a 40% refund (scaled by current strength).

The economic structure that makes frontier territory pay.

• Cost: $1,500
• Strength: 100, Armor: 2, Upkeep: $50
• Radius: 3 sectors.
• Built by: Construction Truck (any owned land sector).
• Research: Infrastructure track, position 15.

How Refineries work

Your country automatically processes resources from your heartland (roughly 5% of the world's land, nearest your capital). Sectors beyond the heartland threshold pay nothing unless covered by a Refinery.

A Refinery extracts resources from every sector within 3 hops of it, subject to two rules:

• Sectors already covered by your heartland gain nothing from the Refinery. Don't waste a Refinery in your core.
• Overlapping Refinery coverage does not stack. Two Refineries whose radii include the same sector only process that sector once.

Refineries also have a second, less obvious effect: every sector inside a Refinery's radius counts as partially covered territory for the diminishing-returns formula, softening the scale-down applied to your total resource income. A sprawling empire recovers some — but not all — of its diminishing-returns penalty by carpeting more of its land with Refineries. See Economy.

The Economy map mode highlights heartland, Refinery-covered, and unprocessed sectors so you can see exactly where a new Refinery would pay off.

Where to place them

• On recently captured frontier territory — the faster you convert conquest to income, the faster you fund the next push.
• Near resource-rich regions. The Resources overlay shows where the richness is concentrated. Drop Refineries where you can cover multiple high-value sectors.
• Where you can defend them. A Refinery that gets destroyed next cycle isn't an asset. Pair Refineries with Turrets, or place them behind your front line.

Losing a Refinery

Refineries are soft — armor 2, strength 100. A single Missile strike often destroys one. When you're under pressure, consider:

• Repairing damaged Refineries (Phase 5).
• Scorching (destroying yourself before capture — see Comeback).
• Selling for a 40% partial refund.

Destroying an enemy's Refineries is one of the highest-leverage offensive moves — it erases their frontier income without touching their heartland.

A forward logistics anchor that extends the supply network without the cost or footprint of a full Land Base.

• Cost: $1,000
• Strength: 150, Armor: 1, Upkeep: $30
• Supply radius: anchors upkeep distance from this sector outward.
• Built by: Construction Truck (any owned land sector — no Land Base, Bunker, or Surveillance Center on the sector).
• Research: Infrastructure track, position 9.

A Supply Depot occupies the same on-map position as a Land Base, so the two can't share a sector. A Bunker uses the same slot too, so Depot and Bunker can't share a sector either.

How Supply Depots work

A Supply Depot seeds the same upkeep-distance graph as a Land Base — every friendly land or air unit measures its distance to the nearest Land Base or Supply Depot when computing its upkeep multiplier. Drop a Depot on the frontier and any units near it pay near-base upkeep rather than long-distance rates.

Depots are far cheaper than Land Bases ($1,000 vs $2,500), build faster, and have lower upkeep ($30 vs $100) — but they don't produce units and they're more fragile (150 strength vs 1,000, armor 1 vs 5). Use them when you want to push your supply network forward without committing to a production hub.

Where to place them

• Along sustained offensive corridors — every few sectors of advance, drop a Depot to keep upkeep from spiking.
• In sea-front rear areas where your ships rely on Sea Bases but your accompanying land units need a closer anchor. (Note: sea units don't use Depots — they only feed off Sea Bases.)
• Behind Turret lines — Depots are soft, so park them where they're already defended.

Depots can be repaired and sold for the standard 40% × strength refund.

A hardened defensive position that toughens up whatever's defending the bunker's sector.

• Cost: $1,500
• Strength: 300, Armor: 5, Upkeep: $20
• Defender armor bonus: +3 (applies to all units defending the bunker's sector).
• Built by: Construction Truck (any owned land sector — no Land Base, Supply Depot, or Surveillance Center on the sector).
• Research: Infrastructure track, position 12.

Bunkers occupy the same on-map position as a Land Base (and Supply Depot), so they can't share a sector with either. Pick the role for that sector: production hub (Land Base), forward supply anchor (Supply Depot), or defensive hardpoint (Bunker).

How Bunkers work

When an enemy attacks a sector containing one of your Bunkers, every friendly unit defending the sector gets +3 effective armor for the duration of the fight. An Infantry (armor 1) defends like a Tank (armor 4); a Tank (armor 3) defends like a Transport (armor 6). The bonus stacks on top of terrain modifiers and the held-since defender bonus.

The Bunker only contributes when defending its own sector — units that attack out of a bunker sector get no benefit at their destination. Bunkers are pure defensive infrastructure.

A Bunker is also a tough structure in its own right: 300 strength (3× a Turret or Refinery) and armor 5, so air strikes have to commit serious payload to crack it.

Where to place them

• On your capital sector. Combined with terrain bonuses and held-since fortification, a capital Bunker makes the final defense extremely punishing.
• At chokepoints you must hold — mountain passes, the only land bridge to your peninsula, the sector hosting your only Refinery cluster.
• Around Air and Sea Bases to keep them hard to overrun even when air defense fails.

Bunkers can be repaired and sold for the standard 40% × strength refund.

A high-end intel structure: pure-radius vision plus passive detection of nearby hidden enemies.

• Cost: $8,000
• Strength: 500, Armor: 2, Upkeep: $60
• Vision range: 5 sectors. Detection range: 5 sectors.
• Built by: Construction Truck (any owned land sector — the sector must hold no other base or structure apart from Defense Turrets).
• Research: Infrastructure track, position 21.

A Surveillance Center is exclusive: no Land/Sea/Air Base, no Refinery, no Supply Depot, no Bunker can share its sector. The only structure it tolerates as a sector-mate is the Defense Turret — keep Turrets around the Center and nothing else.

How Surveillance Centers work

A Surveillance Center contributes two things to its owner's intel:

1. Vision — every sector within 5 hops of the center is current every cycle, no scouting required. This is a much wider permanent vision footprint than the few-hop band around your borders and units.
2. Hidden-unit detection — at the end of each cycle, the Center scans all enemy Spies and Submarines within 5 hops and generates a fuzzy 7-sector "blob" around each one on your map. You see somewhere a Spy is in this area without seeing the exact sector. Blobs are wiped and regenerated each cycle, so a stationary Spy doesn't get pinned down by inference across multiple cycles — you have to act on the lead while it's fresh.

The Center itself is reasonably tough (500 strength, armor 2) but expensive — at $8,000 it's the most costly non-base structure in the game and sits at the end of the Infrastructure track.

Where to place them

• Covering high-value rear assets — capital, Air Bases, Refinery clusters. A Center turns the entire surrounding area into permanent intel coverage.
• Near suspected Spy ingress routes — front-line Spies have to cross your territory to reach the interior; a Center along that approach forces them into the detection blob.
• Not on the active front line — they're expensive and don't fight. Keep them in territory you actually control.

Centers can be repaired and sold for the standard 40% × strength refund.

Invisible area denial for land sectors.

• Cost: $600
• Strength: 100, Armor: 0, Upkeep: $0
• Built by: Mine Layer (land unit) — not Construction Truck.

How Land Mines work

• Invisible to enemies. Your own country always sees its own mines, and active treaty partners can see each other's mines — so allies don't blunder into each other's minefields.
• Enemy countries can also surface a mine if they have a friendly Mine Layer in the mined sector or on a directly adjacent sector (mine layers detect nearby mines).
• When any enemy unit enters a mined sector, the mine triggers and is consumed (destroyed). Paratroopers landing on a mined sector also trigger the mine — paradrops can no longer bypass a minefield.
• A unit that survives the trigger stops moving for that cycle. The attack order stays queued and resumes next cycle.
• One mine per sector — laying onto an already-mined sector is a no-op.
• Mines retain their original owner across capture — if you take a mined sector, the mines stay; if an enemy unit then enters, the trigger fires against them as it would have against you.
• Not sellable — preventing refund exploits.

Trigger resolution

The mine deals armor-scaled damage with a small randomness factor. Damage is calibrated so an average chain of mines kills a unit at the count below:

Armor	Damage per mine	Avg mines to kill
0 (Spy)	80–100 HP	1
1 (Infantry, Rebel, Paratrooper)	40–60 HP	2
2 (Jeep, Helicopter, Spy Plane, Mine Layer, Sea Mine Layer)	28–40 HP	3
3 (Tank, Truck, Warship, Submarine, Jet, Missile)	17–25 HP	5
4 (Transport, Carrier, Frigate)	14–22 HP	6

A Spy that walks onto a mine almost always dies on the spot. A Tank walking a chain of 5 mines ends up dead — but each individual mine just damages and stops it, so the kill takes 5 cycles of advance. Stacking mines along a chokepoint is the way to actually destroy attackers; a single mine just bloodies and delays.

Mine Layers auto-sweep mines they enter — they take no damage and the mine is destroyed. Bring one along if you expect mined terrain.

Tactics

• Mine borders. A ring of mines around your key territory forces enemies to send Mine Layers first or pay damage for every advance.
• Mine chokepoints. Mountain passes, narrow peninsulas, bridge endpoints — any terrain the enemy has to cross is mine gold.
• Clear enemy minefields with your own Mine Layers — they can sweep (remove) mines safely.
• Don't over-mine. Mines cost money and occupy Mine Layer cycles. A few well-placed mines are worth more than a carpet.

Invisible area denial for water sectors.

• Cost: $600
• Strength: 100, Armor: 0, Upkeep: $0
• Built by: Sea Mine Layer (sea unit).

How Sea Mines work

Same rules as Land Mines (armor-scaled damage from the table above, ship stops for the cycle), but deployed on water sectors. Surface ships and Submarines can both trigger them. A Warship takes 17–25 HP per mine and dies in roughly 5 hits; Transports/Carriers/Frigates (armor 4) take 14–22 HP and need 6. A single mine alone won't sink an armored ship, but a chain along an invasion lane will pulp the fleet — and a stop-per-mine effectively grounds the advance until the survivors push through.

Sea Mine Layers auto-sweep enemy mines without taking damage.

Tactics

• Mine your coastlines around Sea Bases to discourage enemy raids.
• Mine approaches to Transports' likely unloading coasts — forces the enemy to sweep before invading.
• Subs can't see mines either. A sea minefield counters stealthy submarine approaches just as well as surface ships.
• Sea Mine Layers sweep enemy mines. If an enemy is mining a strait you want to cross, a Sea Mine Layer makes the crossing safe.

Sector limits on structures:

• Refinery: max 1 per sector. Can't share a sector with a Surveillance Center.
• Defense Turret: max 3 per sector. Always allowed (the only structure permitted on a Surveillance sector).
• Supply Depot: max 1 per sector. Can't share a sector with a Land Base, Bunker, or Surveillance Center.
• Bunker: max 1 per sector. Can't share a sector with a Land Base, Supply Depot, or Surveillance Center.
• Surveillance Center: max 1 per sector. Can't share a sector with any other base or structure except Defense Turrets.
• Mines: max 1 per sector — a Mine Layer trying to lay onto an already-mined sector will move past without consuming the cost.

Land Base, Supply Depot, and Bunker share the same on-map slot (the top of the sector icon ring), so at most one of those three can ever be on a sector. The Surveillance Center also uses that top slot but additionally clears the rest of the sector — only Turrets coexist with it.

Bases and structures do not count toward the 1-unit stacking cap — a sector can hold a Land Base, a Refinery, a Turret, and a combat unit all at once.

Structure	Repair	Sell refund	Notes
Defense Turret	Yes, Phase 5	40% × strength/100	Built by Truck.
Refinery	Yes, Phase 5	40% × strength/100	Built by Truck.
Supply Depot	Yes, Phase 5	40% × strength/100	Built by Truck.
Bunker	Yes, Phase 5	40% × strength/100	Built by Truck.
Surveillance Center	Yes, Phase 5	40% × strength/100	Built by Truck.
Land Mine	No	Not sellable	Built by Mine Layer.
Sea Mine	No	Not sellable	Built by Sea Mine Layer.

Mines are intentionally non-sellable — otherwise you could lay, sell, relay mines as a refund exploit.