Yes, buildings have been destroyed with nuclear weapons (find some photos of Hiroshima or Nagasaki Japan). Conventional explosives were used in WW 2 to bomb cities. Commercial explosives are used...
The game should have all of the maps. There's also like atleast 10 new maps in the skirmish mode plus three multiplayer "operations" maps with different types if gameplay.
Logging (especially clear-cut logging) and strip mining are both biggies - look into companies that do that, but even feed lots can have an big impact on a smaller scale.
It just depends on why...