The Channel Tunnel, sometimes referred to informally as the Chunnel, is a 50.46-kilometre (31.35 mi) undersea railway tunnel, opened in 1994, that connects Folkestone with Coquelles beneath the English Channel at the Strait of Dover. It is the only fixed link between the island of Great Britain and the European mainland. At its lowest point, it is 75 metres (246 ft) below the sea bed and 115 metres (377 ft) below sea level. At 37.9 kilometres (23.5 mi), it has the longest underwater section of any tunnel in the world and is the third-longest railway tunnel in the world. The speed limit for trains through the tunnel is 160 kilometres per hour (99 mph). The tunnel is owned and operated by Getlink, formerly Groupe Eurotunnel.

Folkestone is a port town on the English Channel, in Kent, south-east England. The town lies on the southern edge of the North Downs at a valley between two cliffs. It was an important harbour, shipping port and fashionable coastal resort for most part of the 19th and mid 20th centuries.