I've discussed the problem of mansions popping up all over the place in this thread. I feel that a key part of this issue is that it seems to be too easy to get most of the city up to maximum Land Value. In this screenshot of my previous city, one can see that most of the city is at the highest level of green Land Value. Using the SHIFT + CTL + ALT + Query Tool, I was able to confirm that most of the city was at the maximum allowed Land Value of 255. This means high-wealth mansions can appear pretty much anywhere in the city - the default Medium/High wealth boundary is 120. I've been going through the list of known Exemplar properties trying to find something that might have an effect on this, and have then been creating some modified .DATs to test out in the game. I've been through a few and haven't noticed any effect, but I've now found one that looks very interesting, even though I don't know exactly what it's doing.  There an Exemplar property called: 0x47e2c331    Float32    Land Value Desirability Factors    Size of effects (see IDs) It's default value is 2.5. I changed it to 1. I then loaded up my city and the effect is instantly obvious on the Land Value data map. Instead of most of the city being maximum 255 Land Value, everything is reduced significantly. The highest I could see was 172, and then all kinds of numbers below that. Lots of land had gone below the High-wealth default threshold of 120. So I don't know exactly what's happening here or how it will affect other aspects of the game, but it looks promising.