When a new location is added, the URL might get a “-1” appended. For example
This happens because WP does not allow duplicate slugs, and there already is something else using the slug greece.
This is most likely to be a tag, but can also be something else.
The solution is to search the database for the slug greece and change it to greece-1.
Then search for greece-1 and replace all results (except the one you just changed) with greece.