As promised, here's the first clue. These are pictures of all the cities where I've lived for more than six months:
If you click on the slideshow you can see a bigger version.
So, your first task is to find out the names of the cities. I suggest you start with the country, it should be easy, if you look at the pictures carefully.
This is what we are gonna do, write an entry here telling me what country you think each picture belongs to and I'll tell you whether your guess is right or wrong. When someone has the six countries right, I'll give you the next clue.