History: London, England, United Kingdom

Scope
Greater London is the top-level administrative subdivision covering London. The small, ancient City of London at its core once contained the whole settlement, but as the urban area grew the City Corporation resisted attempts to amalgamate it with its suburbs, causing "London" to be defined in a number ways for different purposes; and the situation was once open to legal debate. Forty per cent of Greater London is covered by the London post town, within which 'LONDON' forms part of postal addresses.
The London telephone area code (020) covers a larger area, similar in size to Greater London, although some outer districts are omitted and some places just outside are included. The area within the orbital M25 motorway is normally what is referred to as 'London'. and the Greater London boundary has been aligned to it in places.
Outward urban expansion is now prevented by the Metropolitan Green Belt, although the built-up area extends beyond the boundary in places, resulting in a separately defined Greater London Urban Area. Beyond this is the vast London commuter belt. Greater London is split for some purposes into Inner London and Outer London. The city is split by the River Thames into North and South, with an informal Central London area in its interior. The coordinates of the nominal centre of London, traditionally considered to be the original Eleanor Cross at Charing Cross near the junction of Trafalgar Square and Whitehall, are approximately 51°30′26″N 00°07′39″W.