10 Downing Street, the home of British prime ministers since 1735, vies with the White House as being the most important political building anywhere in the world. Behind its iconic black door, the most important decisions affecting Britain for the last 275 years have been taken.
In the 20th century alone, the First and Second World Wars were directed from within it, as were the key decisions about the end of the empire, the building of the first British nuclear bomb, the handling of economic crises from the Great Depression in 1929 to the modern day, and the development of the welfare state.
Some of the most famous political figures of modern history have lived and worked in Number 10, including Robert Walpole, Pitt the Younger, Benjamin Disraeli, William Gladstone, David Lloyd George, Winston Churchill and Margaret Thatcher.
Number 10 has overlapping functions. It is the official residence of the Prime Minister: it is their office, and also the place where they entertain guests from Her Majesty The Queen, world leaders and other British and overseas guests from business and charities.