Channel Tunnel

The Channel Tunnel opened in May 1994 after six years of construction and is the longest undersea tunnel in the world. It actually consists of three tunnels running parallel to each other; the two outer tunnels are used for trains and the smaller central service tunnel is used for ventilation and access. The two larger tunnels are wide and are high enough to take a double-decker bus. They curve gently up and down or left and right so that they can run through the chalk strata. On average, the tunnels