11 Downing Street - Credit: Wikimedia Commons
11 Downing Street in London, also known colloquially in the United Kingdom as Number 11, is the official residence of the Chancellor of the Exchequer (who traditionally also has the title of Second Lord of the Treasury). The residence, in Downing Street in London, was built alongside the official residence of the Prime Minister at Number 10 in 1682. Read more on Wikipedia
Source: en.wikipedia.org