SydneyCheck out Sydney. Previously to get near this level of detail for a particular locale you would have to purchase a 3rd party scenery pack and then suffer abominable frame rates.
With the ability to automatically generate buildings, trees, static and flying aircraft and the associated radio traffic this package must have sent shock waves through companies whose business was based on enhancing the Microsoft sims. Still, the open architecture is there and the Pro version even includes an object / aircraft construction kit.
I'd imagine some business plans are hastily being rewritten and in the end we are all better off.
The sim has the ability to support computers and graphic that aren't even built yet - but they will be! Yet it still runs on an average PC and looks good. Who could have imagined 10 years ago that this level of detail and complexity could be modelled on a PC? Only in my dreams!