GustavoPienucci on "Drop Down Option"

Hi everyone,
I am trying to do a drop down menu on my website and it seems that is not as easy as I first expected. Let me describe you what exactly I am trying to do.
I have a review website ( hotels and restaurants ), and I want to include on a page a drop down menu from which visitors can have quick acces to a 3 level "quiz" before returning with the review they want.
Example: They want to check out a restaurant in Paris. First drop down menu, lets them to choose from a list of countries ( they will choose France in this example ). Then the second drop down menu, will indicate a list of cities in France ( Including Paris ). The third one, will give them the reviews available for the selection France=>Paris.
Now, I know that if this thing is possible to make, I will have to update all the reviews I made, giving them "Country" and "City" tags / categories, and therefore, I think this drop down menu will have to create 2 more separate "category" boxes in the "Add New Post" section.
It would be nice to get some help from people who stumbled into this issue.