Mediterranean city's greeting to departing North American spies (8)
I believe the answer is:
valencia
'mediterranean city's' is the definition.
'Valencia' can be an answer for 'city's' (I've seen this before). I am unsure of the 'mediterranean' bit.
'greeting to departing north american spies' is the wordplay.
I cannot quite see how this works, but
'north' could be 'n' ('N' can be a synonym of 'north') and 'n' is present in the answer.
'american' could be 'a' (common abbreviation - e.g. in organisation names) and 'a' is found in the answer.
'spies' could be 'cia' and 'cia' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for valencia that I've seen before include "European city" , "Spanish city and region" , "Region and major port of eastern Spain" , "Spanish port" , "European area" .)