The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain is a sovereign country in north-western Europe, off the north-western coast of the European mainland. It is the 12th-longest coastline in the world.

The United Kingdom is a unitary parliamentary democracy and constitutional monarchy. The capital is London, a global city and financial centre with an urban area population of 10.3 million.

The United Kingdom has the world's fifth-largest economy by nominal gross domestic product (GDP), and the tenth-largest by purchasing power parity (PPP). It has a high-income economy and a very high human development index rating, ranking 13th in the world.

The UK became the world's first industrialised country and was the world's foremost power during the 19th and early 20th centuries. It is a recognised nuclear weapon state and is ranked sixth globally in military expenditure. It has been a permanent member of the United Nations Security Council since its first session in 1946.

The United Kingdom is a member of the Commonwealth of Nations, the Council of Europe, the G7, the G20, NATO, the Organisation for Economic Co-operation and Development (OECD), Interpol and the World Trade Organization (WTO). It was a member of the European Union (EU) and its predecessor, the European Economic Community (EEC), from 1973 until withdrawing in 2020.

Stonehenge Buckingham Palace