The body of water that separates the United Kingdom from mainland Europe is the English Channel. This narrow body of water runs between England to the north and France to the south, connecting the North Sea to the Atlantic Ocean. The English Channel is approximately 21 miles (34 kilometers) wide at its narrowest point, known as the Strait of Dover. This channel has historically been significant for trade, travel, and military movements, and it features various ferry services and the Channel Tunnel, which allows for rail travel between the UK and mainland Europe.