[2021] Historical European buildings popping up?

If you have the European Style enabled, then the European buildings can spawn in any high density zone. To avoid that you can either disable the style or you can apply a district style and set it to International or Default - that will make sure that none of the European ones spawn.

Originally posted by kristofburger:

Originally posted by CO_Avanya: If you have the European Style enabled, then the European buildings can spawn in any high density zone.

In vanilla, European buildings will not spawn outside of a designated district if the map theme is not European. The OP is on the tropical theme, which means the automatic mixing of growables is caused by a mod (probably Building Themes as mentioned previously).

You are entirely correct. Thank you for pointing out my mistake!