No 10 Downing Street is a historic building that is also a place of work. It is a symbol of Government known the world over and is the home to the Prime Minister and his family.
From the outside, the plain Georgian frontage with its famous black door appears too small to accommodate all these roles. Inside, the building opens out to reveal a series of elegant state rooms, used both for official receptions and everyday meetings. Offices for the staff of the Prime Minister's Office are crammed into every spare space.
Yet despite the role of No 10 as a nerve-centre of Government, running day and night for every day of the year, there are opportunities for school parties and others to glimpse inside.
"Downing Street" and "No 10" are also short-hand for the Prime Minister's Office, the team of officials and special advisers who support the Prime Minister and ensure he can carry out his wide range of functions, from international diplomacy to policy-making.
Find out more about the work of the Prime Minister's Office.
See how No 10 works with the Cabinet Office and other departments to provide direction and co-ordination at the centre of Government.