Greater London is often referred to as "the City" or "the Square Mile" and it forms the main financial district. Archaically, the urbanised area of London was known as the Metropolis. In common usage, the terms "London" and "Greater London" are usually used interchangeably. Greater London is officially divided for some purposes, with varying definitions, into Inner London and Outer London. For some strategic planning purposes it is divided into five sub-regions. Greater London is under the strategic local governance of the Greater London Authority (GLA). It consists of an elected assembly, the London Assembly, and an executive head, the Mayor of
City of London east (downstream), cross the River Thames: Blackfriars Bridge, Blackfriars Railway Bridge, Millennium Bridge (footbridge), Southwark Bridge, Cannon Street Railway Bridge and London Bridge; Tower Bridge is not in the City. The City, like most of central London, is well served by buses, including night buses. Two bus stations are in the City, at Aldgate on the eastern boundary with Tower Hamlets, and at Liverpool Street by the railway station. There are approximately 28 Barclays Cycle Hire docking stations in the City. A number of existing and proposed cycle routes criss-cross the City, as part of the London Cycle Network. One