Question: Montfichet's Tower was a Norman fortress on Ludgate Hill, in the historic centre and central business district of which city? 
Sentence (from "City of London"): Administratively, it forms one of the 33 local authority districts of Greater London; however, the City of London is not a London borough, a status reserved for the other 32 districts (including London's only other city, the City of Westminster).
Relevant evidence: No