I built a City Hall that has an exposed center and I noticed that I could see the tops of mushroom caps protruding through the base of the foundation. It seems that the game is generating the mushroom assortment deco under the foundation on its own.
When I saw this, I clicked to grab it and it crashed the game... I restarted the game and just ignored it but the next day I was clearing everything from one of the captured cities so I could set up everything the way I want it. Well, not really thinking too much about crashing the game the day before, I clicked to grab the shrooms and crashed the game again... This is in the space stage by the way..... The second really burned me because I had spent about an hour or more on a newly captured planet terraforming and setting up new cities and POOF, all gone.
Anyway, I thought it would be good to pass this info along.
There needs to be some kind of auto save that saves the game while you're playing every 15 minutes or so.
I use the save feature and I use it very often but since you can't save while you're on a planet (space stage) or while doing tasks like city planning it can be really painful if the game crashes.