The United Kingdom of Great Britain and Ireland (commonly known as the United Kingdom, the UK, or Britain) is a sovereign state located off the northwestern coast of continental Europe. It is an island country, spanning an archipelago including Great Britain, Ireland, Gibraltar, and many small islands. Gibraltar is the only part of the UK with a land border, sharing it with the Spain and Morocco. 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.