The article reviews the history and preparation of the Channel Tunnel, discussing recent studies and the implications of private financing for such a large project. Two valid construction routes have been identified: a bored tunnel in the lower chalk or an immersed tube in a sea bed trench. The decision on construction type may depend on contractor terms. The tunnel will offer 24-hour service with trains departing every five or ten minutes during peak times. The costs of the tunnel have been examined.