The Cathedral of Plentitude is a level 6 unique building in Cities: Skylines. Unlocking it requires reaching the ‘Small City’ milestone and having 30 different types of city service buildings.
Only one instance of each service building type counts towards your progress (e.g., even if you have 4 wind turbines in your city, it will only count as one). Also, the 30 buildings all need to be operational at the same time in order to count.
At the time of writing, service buildings from the Green Cities and Sunset Harbor DLC count towards your progress, making this much easier to accomplish.
If you’re playing only on the vanilla version of the game, you’ll need some expensive late-game buildings such as the airport and nuclear power plant to make up the 30.
Here are the buildings that can count towards your Cathedral of Plentitude progress, as well as their required milestones and costs.
Coal Power Plant
Advanced Wind Turbine
Oil Power Plant
Solar Power Plant
Nuclear Power Plant
Geothermal Power Plant
Solar Updraft Tower
Towards the late game, you likely will have gotten rid of any coal or oil power plants in favor of cleaner and more efficient power sources; in this case you’ll have to build new ones and have them running just until you’ve unlocked the cathedral.
Liz is a writer and photographer with a love for building and strategy games. Her spare time is often split between lifting, reading, drawing, annoying her dog Mr. Porky Butt, and squinting at stat tables on the wiki pages of whatever game she's currently playing.