The United Kingdom (UK) is an island nation located off the northwestern coast of mainland Europe. It comprises four countries: England, Scotland, Wales, and Northern Ireland. Together, England, Scotland, and Wales form Great Britain, while Northern Ireland shares the island of Ireland with the Republic of Ireland. The UK is a constitutional monarchy with a parliamentary democracy, where the monarch is the head of state and the prime minister is the head of government. London, the capital, is a major global city. The UK has a rich cultural heritage and has made significant contributions to global culture, economy, and politics.