Question: Montfichet's Tower was a Norman fortress on Ludgate Hill, in the historic centre and central business district of which city? 
Context: There are more than 50 tall buildings in Oklahoma City, most of which stand in the central business district.  In the city, 17 buildings stand 250 ft and taller.  The tallest building in Oklahoma City, and in Oklahoma, is the 50-story Devon Tower, which rises 844 ft in the central business district.  Other notable skyscrapers are Chase Tower and First National Center, which stand as the second and third-tallest buildings in Oklahoma City, respectively.  Six of the 10 tallest buildings in Oklahoma are located in Oklahoma City. Wheeling Historic District, also known as the Wheeling Central Business District, is a national historic district located at Wheeling, Ohio County, West Virginia.  The district includes 205 contributing buildings in the central business district of Wheeling.  It includes the site of the original location of Fort Henry.  The buildings are representative of a number of popular architectural styles from the early-19th century through the present including Greek Revival and Late Victorian.  The District was listed on the National Register of Historic Places in 1979. Gladstone Central is a suburb in the Gladstone Region, Queensland, Australia.  It is the historic centre and central business district of the city of Gladstone and the seat of the Gladstone Regional Council.  In the 2011 census, Gladstone Central had a population of 1,529 people. Montfichet's Tower (also known as Montfichet's Castle and/or spelt Mountfitchet's or Mountfiquit's) was a Norman fortress on Ludgate Hill in London, between where St Paul's Cathedral and City Thameslink railway station now stand.  First documented in the 1130s, it was probably built in the late 11th century.  The defences were strengthened during the revolt of 1173–1174 against Henry II. The Central Business District is one of seven development districts in Saskatoon, Saskatchewan, Canada.  The central business district is Ward 6 of a Mayor-Council government represented by councillor Cynthia Block.  Formerly called West Saskatoon, this area arose when the steam engines built their pumping stations on the lower west bank of the South Saskatchewan River.  Retail enterprises sprang up around the newly created train station and rail yards.  The city of Saskatoon's Central Business District has shopping malls and boutiques. Downtown McAllen is the main business district in McAllen, Texas.  U.S. Interstate 2 runs directly south of the downtown area.  The City's Central Business District and encompasses the area west of 10th street, east of Bicentennical, south of Hackberry and north of Interstate 2.  This area thrives from over 250 retail businesses, the Federal building Bentsen tower, McAllen city Hall, the Mexican Consulate, the Honduran Consulate, the Guatemalan Consulate, Medical offices, banks, the City's Bus Terminal McAllen Central Station and Downtown Parking Garage.  It is estimated that 5,516,000 pedestrians visit the Central Business District.  The two tallest towers in the area are the Chase Tower and the Bentson Tower.  17th Street in Downtown is lined with many bars, pubs, lounges, restaurants, and music venues.  It is also home to the historic Cine El Rey. The Rogers Commercial Historic District is a historic district in the central business district of Rogers, Arkansas.  When it was first listed on the National Register of Historic Places in 1988, it was known as the Walnut Street Historic District; this was changed when the district was enlarged in 1993.  The district encompasses a portion of the city's central business district, whose historical significance extends from about 1885 to the end of the Second World War. Tower Hill is an affluent government and residential neighborhood in central Freetown, Sierra Leone.  Tower Hill is located within the central business district in downtown Freetown.  Tower Hill is the seat of the government of Sierra Leone, as it is home to the State House (the office and residence of the Sierra Leone president).  Tower Hill is also home to the Sierra Leone House of Parliament, the Sierra Leone Ministry of Defence, the Bank of Sierra Leone , The Sierra Leone National Electoral Commission (NEC) , and many other government buildings. The City of London is a city and county that contains the historic centre and central business district of London.  It constituted most of London from its settlement by the Romans in the 1st century AD to the Middle Ages, but the agglomeration has since grown far beyond the City's borders.  The City is now only a tiny part of the metropolis of London, though it remains a notable part of central 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). Downtown Orlando is the historic core and central business district of Orlando, Florida, United States.  It is bordered by Marks Street in the north, Mills Avenue (SR 15) in the east, Orange Blossom Trail (US 441) in the west, and Kaley Avenue in the south.  There are several distinct neighborhoods in downtown; "North Quarter" to the north, "Lake Eola Heights Historic District" just north of Lake Eola, "South Eola" to the east and south of Lake Eola, "Thornton Park" in the east, "Parramore" in the west, "Lake Cherokee Historic District" to the south, and the "Central Business District" (or the "Financial District") between Colonial Drive and Lake Lucerne in the center.  In 2010, the estimated population of downtown was 18,731.  The daytime population was estimated to be 65,000 (in 2010).  The 5-mile radius population of downtown is 273,335.
Answer: City of London