I have been trying to figure this out for a few days now and looked at lots of examples but can't find anything similar to get ideas from.

I have a forum / site for international travel and chat and I am working on adding a directory, the problem is I don't know how to structure the categories.

Because it is worldwide, I can't go too specific.

For example should I start with continents then go down to main countries and then do categories for hotels, travel agents etc.
Or simply start with countries and do the categories..

Or...I really don't know...

I can't add all countries because it is simply too wide an area to add a category for each.

Hopefully someone has a more structured mind than me

Thanks for any help!