Well, let's see what you will need in terms of collections to build your app:
Collection storing the Places you want to use in your app. This would be your main collection and would contain among other things a map location object {longitude: XXX, Latitude YYY}
Because you probably want people to be able to search by city, country, etc.. You need either a collection per Location type (city, country, etc) or a table with all the locations and a "type" flag that indicates the location is city or country, etc....
3.- You need a table that allows you to start at a country and drill down to a particular set of cities (for example). So, you need a table with a from key and a to key
By this point you probably have noticed that we have basically built a hierarchy, which in Arango I would build as at least one Places vertex collection, a Locations vertex collection and a locationContains edge collection. This would allow for really fast lookups and is one of the reasons why graph databases were originally created.
Now note that since Arango is a multi model DB, you can use the graph syntax (I like anonymous graph syntax myself), but you can also use traditional joins whenever needed, which behave very similar to a traditional relational DB.