The English Channel is a body of water that separates the island of Great Britain from the rest of Europe. People who live in the UK and want to visit Europe, or people from Europe who want to visit the UK, can take a ferry across or ride a train under the channel in a special tunnel called the Channel Tunnel (nicknamed the "Chunnel"). Both the ferries and trains carry cars. It is 563 km long, 246 km wide, and its narrowest part (34 km) is the Strait of Dover. On a clear day, it is possible to see the cliffs of Dover from Calais on the French side.