Disasters
Yes, disasters happen all of the time, and unfortunately for Civville, they happen there too. At this time there are 2 possible disasters in the game. I will describe them in the following sentences.

| Monster: Yes, even the big disgruntled monster makes it to your city occasionally. If this comes to the city early in the game simply reload your last saved game because it is likely that you do not even have a chance at beating off this creature. It takes hundreds of regular units and tens of terrorists to bring the big guy down and if it takes a city, expect to see more than one and that is a very, very bad thing. Perhaps you can take over the city before the Monsters do? However, it is likely you may not see this beast at all during your scenario.
| It is far more likely you will see a tornado hit your city rather than a Monster. These are less destructive and dissapate after hitting its target.