English Channel tunnel

When and if engineers build the long-planned tunnel connecting France with Britain under the English Channel, the new U.S. Chesapeake Bay Bridge-Tunnel, about to carry traffic, will receive some of the credit for making it possible. England sent two engineers to work on the mammoth bridge-tunnel, which has been called one of the five future wonders of the world…. The recent agreement between British and French Governments to build the Channel tunnel calls for twin 32-mile-long tubes in which electric trains will speed back and forth…. The ventilation problem of exhaust fumes in such a long tunnel would be too difficult to permit auto traffic. 

Update

First proposed in 1802 as a tunnel for horse-drawn carriages, the Channel Tunnel, or Chunnel, was built starting in 1987 and opened in 1994. The tunnel carries high-speed trains and automobiles, with a service tunnel and towers providing ventilation. Chunnel operations have been suspended at times by fires, cold weather and illegal immigration problems.