Depends on the scale you're working with. I work in 1/35, so an entire city block would require a base the size of my work room! Not that I wouldn't love to build something that huge... one day![Big Smile [:D]](/emoticons/icon_smile_big.gif)
Smaller scales might be a better way to get eveything in that you want to make. Be a little more specific about what it is that you want to know, maybe we can figure it out with you. As you work through your project, ask ??? along the way.
A quick answer is: Look around on ebay for pre-made ceramic and/or resin structure facades by Verlinden, Custom Dioramics and the like. Most of them come already partially destroyed, if that's what you want. Glue 'em together, prime 'em, paint 'em and secure them to a base. Go to Hobby Lobby or Michael's and buy a bunch of balsa and basswood to make the interior walls, floors. It's cheap. Get a good ruler. A good mider box is almost a must.
Some say it's wise to start small. Consider it "practice". But do what you want... all projects are practice for the next ones anyway.
Just make sure you've got enough space to display the sucker when finished.
Steve