There’s been a mini-craze online for creating tilt-shift photos, where the focus position and depth of field on a landscape/cityscape are manipulated to make the picture look like a miniature reproduction. For authentic tilt-shift photos, you need a special lens, but you can re-create the effect using Photoshop filters, or by following tutorials online. Now there’s an online website called TiltShiftmaker that lets you upload your own photos, and applies a tilt-shift effect to them:
Original photo from the island of Santorini (from Flickr):
Run through TiltShiftmaker:
The process works best on images that don’t have a few objects much taller than the rest of the scene, as that can result in the base of the object being at a different focus/blur than the top.