African giant contrived to annex northern city (7)
I believe the answer is:
pompeii
'city' is the definition.
(Pompeii is an example)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for pompeii that I've seen before include "Buried Roman city" , "Roman site" , "Vesuvius-buried town" , "Ancient site" , "Town buried by Vesuvius 1st century a.d." .)