The
Channel Tunnel (; also referred to as the
Chunnel) is a rail
tunnel linking
Folkestone, Kent, in the United Kingdom, with
Coquelles, Pas-de-Calais, near
Calais in northern France, beneath the
English Channel at the
Strait of Dover. At its lowest point, it is deep. At , the tunnel has the longest undersea portion of any tunnel in the world, although the
Seikan Tunnel in Japan is both longer overall at and deeper at below sea level. The speed limit in the tunnel is .