Two big rivers, the Rio Paraná and the Rio Uruguay, cut the Argentine
provinces of Entre Rios, Corrientes, and Misiones off from the rest of the
country so completely that they can only be reached by ship or by air.
That of course entails such transport delays that the whole economy suffers
as a result. The government therefore decided in 1960 to build a tunnel
under the water between the cities of Santa Fé and Paraná.

In 1964 a joint venture headed by HOCHTIEF started its work. The procedure
chosen was to build tunnel elements in a dry dock and then float them into
position and sink them. The tunnel was completed in 1969 and was not only
the first of its kind anywhere in South America but also the first fixed link
between the left and right banks of the Rio Paraná.