The United Kingdom of Great Britain and Northern Ireland is a country to the northwest of mainland Europe. It comprises the island of Great Britain, the northeast part of the island of Ireland and many small islands. Northern Ireland is the only part of the UK with a land border, sharing it with the Republic of Ireland.Apart from this land border, the UK is surrounded by the Atlantic Ocean, the North Sea, the English Channel and the Irish Sea. The largest island, Great Britain, is linked to France by the Channel Tunnel.
The UK was the world's foremost power during the 19th and early 20th century, but the economic cost of two world wars and the decline of its empire in the latter half of the 20th century diminished its leading role in global affairs. The UK nevertheless retains significant economic, cultural, military and political influence and is a nuclear power, with the second highest defence spending in the world.
It is a European state, and has many cultural links with its former colonies, particularly those that use the English language (the Anglosphere). The origins of the UK as a political union of formerly independent states has resulted in the preservation of distinctive cultures in each of the home nations.
