It came to me as something of a surprise just how easy it is to mislead someone into thinking they're looking at a photo of a model when they're actually looking at a photo of the real thing.
If you want to spend a lot of money and do this the "right" way, you can buy a tilt/shift lens like this one. When you do so, you can get results like these by Olivo Barbieri (story, more), Marc Räder, Miklos Gaál, or Håmish Gránt.
However, it's a truth generally acknowledged today that any technique that requires pieces of aspherically curved glass can also be done with bits, quicker, safer, cheaper, more repeatably, with more chances to tweak the results, and so on.
So, if you want to make pictures like these but don't want to spend a ton of money doing it, you can actually fake it pretty easily.
How easily? Well, here's my first attempt (before, after) which was OK, but not as convincing as I'd hoped. So then I tried again with a photo from Singapore (before, after) which I tweaked more extensively. Compare, especially, the perspective change between the before and after.
Once I got the technique more or less down, the next two (Harper's Ferry, WV before and after, and Wellington before and after) took only a few minutes each.
If you want to know how I did this, leave a comment.