filter navigation, site content, etc I am really new to Drupal, so this is a beginners question. 
I need to create a website with a dropdown within the header, where visitors can choose a region (not a language, just a region, like "Europe", "US", ...). The entire page should be filtered according to this selection, so if the visitor chose "US", some parts of the navigation or parts of the content should not be visible. 

Is this possible with drupal? 

And, more importantly: how would you go about this? The only thing I could think of is create a taxonomy for each "region" and assign content items and navigation items. Is that a good idea? Is there a better way to go? 

I'd be thankful for any suggestion. Thank you.
I'd try this link. So install that then apply some classes to the menu items that you can use in JQuery to target the links and have the dropdown links trigger them to show/hide. I'm willing to provide further explanation if there's something you're unclear of. Sadly there is no current module or plugin to provide this functionality that I know of.