What is the capital of the United Kingdom?

London is the capital of the United Kingdom and serves as its political, economic, and cultural center. It is one of the most well-known cities globally and hosts significant institutions, including the Parliament of the United Kingdom, the official residence of the Prime Minister at 10 Downing Street, and the British monarchy's ceremonial headquarters at Buckingham Palace.

Additionally, London is home to numerous museums, galleries, and landmarks such as the Tower of London and the British Museum. While Edinburgh, Dublin, and Cardiff are capitals of Scotland, Ireland, and Wales, respectively, they do not serve as the capital of the entire United Kingdom, making London the correct choice for this question.