Nothing remains same forever. Some photographers have visualized this concept with the help of photos and software available. The result, is incredible.
Worth1000 site conducts contests on creative photo manipulation works (they call it photoshoping). The pictures I am talking are from the 49 entries so far in the contest.
Time changes everything. Sometimes, a few days is enough to make a noticeable difference; other times it takes years or even centuries. But eventually, everything starts to show its age.
In this contest, you're asked to speed the process up. Take any object you like, living or inanimate. Leave half (or thereabouts) of the picture untouched. Take the other half, and show how the subject will look at some point in the future.
You can choose the obvious targets: Show a girl's face, with the right half aged to an elderly woman. Or perhaps a new mansion, with one half dilapitated and neglected. Or you can be creative: Put a caterpillar on one half of your entry, changing into a butterfly in the other. It's up to you.
You can see the thumbnails of the entries here. It's worth a look.
And it is great to read the comments too.