This us what people thought when they heard about the tunnel in 1986:

Channel Tunnel, also called Eurotunnel, rail tunnel between England and France that runs beneath the English Channel. The Channel Tunnel, 31 miles (50 km) long, consists of three tunnels: two for rail traffic and a central tunnel for services and security. The tunnel runs between Folkestone, England, and Sangatte (near Calais), France, and is used for both freight and passenger traffic. Passengers can travel either by ordinary rail coach or within their own motor vehicles, which are loaded onto special railcars. Trains can travel through the tunnel at speeds as high as 100 miles (160 km) per hour; the trip takes about 35 minutes.

Channel Tunnel

The often-considered idea of constructing a tunnel under the English Channel was revived in 1986 by the United Kingdom and France. A rail tunnel was chosen over proposals for a very long suspension bridge, a bridge-and-tunnel link, and a combined rail-and-road link, and the project was privately financed by a consortium of British and French corporations and banks; the Anglo-French company operating the tunnel is called Eurotunnel. Digging began on both sides of the Strait of Dover in 1987–88 and was completed in 1991. The tunnel was officially opened on May 6, 1994.

In June–July 2015 the problem of migrants—many of them from eastern Africa—sneaking aboard vehicles on trains in an attempt to immigrate to the United Kingdom reached crisis proportions. During that period at least nine individuals were killed while trying to make their way to England via the tunnel. The United Kingdom and France stepped up security measures to try to deter migrants from attempting the crossing.