In 1969, plans were made for a road tunnel under the Swiss Alps. On this date, the then longest tunnel its kind opened in Switzerland. It is called Gotthard Road Tunnel, and it is now the third longest road tunnel in the world.
More info:
https://travel.yahoo.com/blogs/compass/september-5-st-gotthard-tunnel-opens-switzerland-date-190728481.html
http://en.m.wikipedia.org/wiki/Gotthard_Road_Tunnel
