Avenge the destruction of a city (6)
I believe the answer is:
geneva
'city' is the definition.
(Geneva is an example)
'avenge the destruction' is the wordplay.
'the destruction' is an anagram indicator.
'avenge' with letters rearranged gives 'GENEVA'.
'of a' is the link.
(Other definitions for geneva that I've seen before include "Calvin's city" , "Swiss city/lake" , "Avenge in Swiss city" , "city of biblical significance" , "Some bands" .)