In Civ VI, most districts have a fixed sequence of buildings to be constructed while progressing through the tech tree. A handful, however, have mutually exclusive options at one of the building tiers. I think this mechanic is heavily underused and could be expanded to create more interesting city management dynamics. Below is my draft of what such a system could look like. In choosing building bonuses, I tried to keep the following objectives in mind: 1.) Create new opportunities for city specialization. A number of district and buildings have multiple functions (ex. city defense and military production in encampments). Building choices should allow a player to double down on one of these functions at the expense of the other on a city by city basis. 2.) Provide additional reasons to care about terrain and resources. Adjacency bonuses are a really interesting piece of city planning in Civ VI, but they’re mostly limited to the initial placement of districts. Buildings with additional terrain and resource bonuses should provide incentives to choose between competing buildings and opportunities for advanced players to plan ahead. 3.) Allow players to avoid wasted duplication of bonuses. As regional effects don’t stack (with the exception of Magnus’ Vertical Integration promotion) and a single city can produce only one trade route capacity (without wonders) bonuses from markets, lighthouses, factories, zoos etc. often end up being wasted. Allowing alternatives to these buildings means that players have more choices about whether and how to avoid this duplication. 4.) Reduce flat yields and automatic great person points. Currently, the main way for a player to increase science or a similar yield is simply to build and fill more of the appropriate district. While this should certainly be one piece of the solution, putting those districts in the right places and developing their cities and surroundings appropriately should play a much larger role. Similarly, great person races should depend more on active choices rather than being largely automated based on building counts. In these descriptions, I’ve been very aggressive about editing out flat yields and great person points, but if I’ve gone a bit to far it would be easy to add some of these back in without changing any new/unique features. Holy Site Tier 1: Shrine +2 Faith, +1 GPP Reliquary Provides one Relic slot Tier 2: Temple +4 Faith; +2 GPP; allows the purchase of Apostles etc. Festival Grounds- doubles pantheon bonuses in this city Tier 3: Worship Buildings At Tier 1, the shrine remains the obvious early game option for a player aiming to found a religion, while the reliquary (which could unlock a bit later) aims to support players pursuing religious tourism. At Tier 2, the Temple continues the focus on founding and developing a religion while the Festival Grounds is more appealing in cities benefiting heavily from a Pantheon belief (especially for players who aren’t interested in developing a religion but want to build holy sites for follower beliefs and to earn faith for great people, national parks etc.). Tier 3 retains the current worship building mechanism, which already provides plenty of options (though a few of these could use balance tweaks). Campus Tier 1: Apothecary +1 Food from cocoa, coffee and tea; +1 Science from honey, spices and tobacco; +1 GSP if this increases the yield of 3 or more tiles School of Mathematics +1 Science; +1 GSP; Siege units produced in this city start with 1 free promotion Library +1 Culture and +1 Science from international trade routes arriving in this city Tier 2: University +33% science from population in this city, +1 GSP, and +1 GPP (of the appropriate type) in each adjacent district Observatory +2 science from adjacent mountains; -2 science from adjacent districts and city centers Tier 3: Research Lab +2 Science from Uranium, Mercury and Aluminum; +8 Science if powered (requires 4 power) Public School +33% science from population in this city, +33% additional science from population if powered (requires 2 power) At Tier 1, little direct science is available, but this can be altered through resource availability or cultural exchange, the buildings have substantial ancillary benefits. At Tiers 2 and 3, the university and public school are appealing options, doubling science from population and enhancing great person production in adjacent districts, while the observatory and research lab instead depend on terrain, resources and power availability. Theater Square Tier 1: Amphitheatre +2 culture, +1 GWP; 2 Great Writing Slots Promenade +2 culture and +2 tourism for each adjacent wonder Forum +4 culture Tier 2: Art Museum +2 GAP, +2 culture and +1 GAP from dyes and marble, 3 Great Artwork Slots (provide minor culture and major tourism) Archaeological Museum +4 culture from archaeology and shipwreck sites, 3 Artifact slots (provide major culture and minor tourism); allows production of archaeologists Natural History Museum +2 science from quarries and amber, 3 fossil slots (provide science and tourism); allows production of paleontologists Tier 3: Broadcast Center +2 culture (6 tile regional bonus); When powered, this regional bonus also provides +1 amenity; +25% tourism to all civs with at least 1 city within 6 tiles of a powered broadcast center Concert Hall +4 Culture; +2GMP; 2 Great Music Slots Here, early options provide choices about whether to pursue culture as a path through the civics tree or towards the goal of a culture victory. The Promenade and Broadcast Center provide additional tourism options that aren’t directly tied to great work generation, and the Natural History museum supports hybrid strategies between scientific and cultural paths. Commercial Hub Tier 1: Market Trade routes arriving in this city provide the sending and receiving city +1 gold for each luxury resource present in one city but not the other Caravansary +1 Trade route capacity; this city automatically acts as a trading post for all trade routes, +1 gold for foreign trade routes passing through this city Tier 2: Bank +4 gold, receive 500 gold when constructed Mint +4 gold from silver and copper Tier 3: Stock Exchange +2 Gold; +6 Gold when powered; +2 GMP Commodity Exchange Bonus resources in this city provide gold equal to the number of that resource present (that is, 3 wheat resources in the same city would produce +3 gold each, for a total of +9 gold). Currency Exchange +2 gold to each player for international trade routes originating or arriving in this city. Civs sharing such a trade route generate +25% tourism towards one another The Tier 1 commercial options both focus on trade routes, but do so in different ways, with the market most attractive in large cities with diverse resources and the caravansary preferable at convenient waystations. At Tier 2, I considered a loan mechanism for the Bank but realized an upfront gold payment would be a much simpler way of generating a similar gameplay dynamic. Harbor Tier 1: Lighthouse + 1 Trade Route; This city automatically acts as a trade post for all trade routes; + 1 GAP Fisher’s Docks +1 Food from coastal tiles; +1 production from coastal resources; +2 Housing Tier 2: Drydocks provides production equal to this district’s adjacency bonus; +50% production towards naval units Shipping Docks trade routes arriving in this city provide +1 production to both cities Tier 3: Seaport +2 gold from coastal tiles; +2 gold from coastal resources; +2 Housing Cruise Port +2 gold and +2 tourism for seaside resorts in this city, doubled if powered. Naval Port increased fleet and armada production; +1GAP; Naval Units produced in this city start with a free promotion This is one of the districts I’m less confident about. My goal was to separate out bonuses to allow players to choose between focusing on coastal tiles, trade, and naval production, but those choices seem potentially painful in a lot of cases, and outside the Cruise Port, I don’t have as many ideas about bonuses to add as for many of the other districts. Industrial Zone Tier 1: Workshop +6 production towards civilian units Architect’s Guild +4 production towards buildings and wonders; +1 GPP Smithy +6 production towards military units Tier 2: Factory +3 production (regional effect), additional +3 when powered Depot +3 production from domestic trade routes arriving at this city, additional +3 if the sending city is connected by rail or water Foundry +2 production from iron, coal and oil Tier 3: Coal Power Plant Oil Power Plant Nuclear Power Plant At Tier 1, players can specialize cities for expansion, internal development, or military production. At tier 2, having options other than the factory makes overlapping regional effects easier to avoid. The depot essentially allows the use of trade routes to extend a factory-like effect to new cities that may be out of range, and the foundry doubles down on local production in cities with rich strategic resource deposits. Tier 3 already has three well differentiated options thanks to gathering storm (though the oil plant could perhaps be made a bit more effective. Entertainment Complex Tier 1: Arena +1 amenity; +1 additional amenity for each adjacent horse; +25% experience for land units trained in this city Gardens specialists in adjacent districts require half the usual amenities Fair Grounds farm and pasture workers within two tiles require half the usual amenities Tier 2: Zoo +1 science from rainforests and marshes; +1 amenity if you have an unimproved ivory resource in your empire; +1 amenity if you have an unimproved fur resource in your empire. These bonuses increase to +2 if the unimproved resource is in this city. Circus +2 amenities (regional effect) Tier 3: Stadium +2 amenities (regional effect, increased to +3 if powered); +25% experience gain for units trained in this city. Cinema +2 amenities; +4 culture; +4 tourism (all doubled if powered) Amusement Park +1 amenity for every 6 population; +1 amenity for every 4 population instead if powered At tier 1, the arena (now boosted by horses remains the baseline building), while the gardens and fair grounds allow specialization of amenity consumption for specialist-based or agricultural cities. At Tier 2 the zoo benefits from rainforest, wetland and wildlife conservation, while the circus gains the regional effect (representing their travelling nature). At Tier 3, the stadium continues on the regional effect path, while the amusement park benefits a single, highly populated city and the cinema supports a hybrid amenity/tourism focus. Encampment Tier 1: Barracks +1 production from adjacent mines, +50% experience gain for melee and anticav units trained in this city Stable +1 production from adjacent pastures, +50% experience for heavy and light cavalry units trained in this city Firing Range +2 production, +50% experience for ranged class units trained in this city Tier 2: Drill Field Land units produced by this city start with a free promotion; +1GPP Armory +5 combat strength and +5 ranged strength for this city and any friendly units within its borders Tier 3: Military Academy All units produced by this city start with a free promotion; +2 GPP Recruiting Center Increased corps and army production; this city gains bonus production equal to its population when building land units Bunker +20 city defense against bombers and artillery; population loss and wall damage from nukes reduced by 50% Tier 1 retains the barracks/stable choice but adds mine and pasture adjacency effects to create city specific incentives and splits out a firing range option for ranged units. At tiers 2 and 3, players can choose to emphasize the encampments military production bonuses or its defensive ones, and tier 3 further differentiates the military production choice into a quantity focus and a quality focus. Aerodrome standard adjacency (gold) for city center and commercial hub districts; minor adjacency for flat tiles; -1 appeal on adjacent tiles; +100% production towards air units Tier 2: Communications Airfield +1 gold to both cities for trade routes arriving in this city; +1 access level and +25% alliance growth with civs with a city within 6 tiles of a communications airfield Training Airfield Air units trained in this city gain a free promotion Tier 3: Air Base Air units trained in this city gain a free promotion. Air units based in this district gain +5 combat and ranged combat strength. This district has hit points and combat strength as a city center or encampment but does not gain walls or ranged attacks. Conference Center provides a major adjacency bonus and +1 GPP per level of your strongest alliance to adjacent districts. Hotel Complex +100% tourism from culture generating tiles in this city This is the one district where I couldn’t resist changing my district itself. My thinking is that aircraft should be available at twice the current cost in any city, or at the current cost in a city with an aerodrome. For the buildings themselves, I split bonuses for combat aircraft from communication and tourism bonuses. I’d also be tempted to add oil costs to some of the advanced building to emphasize non-military factors in the climate system, but that’s probably beyond the scope of this discussion. What are your thoughts on such a system of competing buildings? Are there additional options's you'd add? Opportunities I missed to include resource bonuses? Any ideas about the Water Park or Neighborhood? I'd be very interested to see more ideas or discussion on this topic.