What does this number measure?
The tunnel connects the areas of Coquelles, near Calais, and Folkestone. The complex includes two railway tunnels and a service tunnel; about 37.9 km of the route is under the sea. The compared dimension is the total length, including the underground land approaches, not just the underwater section. The illustrated profile is interpretative.
Compare the stated dimensions
The comparison uses the number in each fact sheet: altitude, height, diameter, length or distance, depending on the reference. Two values in metres do not necessarily describe the same property.
Source and limitations
Rounded documented total length; the undersea section is shorter. The cross-section's profile and thicknesses do not constitute a technical survey.
Interpreted longitudinal cross-section of a tube, with its profile and height greatly exaggerated. The compared length is the full route of approximately 50.45 km, including the land approaches; the roughly 37.9 km beneath the sea are only part of it.
Opening: 1994. Proposed historical date; an existing documentary source is linked but was not consulted for this date in this session. Do not interpret this reference as the manufacturing date of the illustrated specimen. Date of the tunnel's inauguration; construction began before that year.