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 is also unusual in having responsibilities and ownerships beyond its boundaries. The Corporation is headed by the Lord Mayor of the City of London, an office separate from (and much older than) the Mayor of London. The current Lord Mayor, as of November 2018, is Peter Estlin. The City is a major business and financial centre. Throughout the 19th century, the City was the world's primary business centre, and it continues to be a major meeting point for businesses. London came top in the Worldwide Centres of Commerce Index, published in 2008. The insurance industry is focused around the eastern