Tunnel Under the Border

Tunnels under the border aren’t anything new but they’re usually about smuggling. I can think of several examples off the top of my head including tunnels between Mexico and the USA for drugs, Egypt and Gaza for basic goods, and the former East and West Berlin for people. Those are all interesting and I don’t wish to diminish their importance. However, I drew my attention to a different border tunnel with a purpose completely unrelated to smuggling.

So let’s go to Salzburg, Austria where the story begins. There the city name translates literally into Salt (Salz) Castle (Burg). It sits along the Salzach River, further emphasizing the mineral. It doesn’t take an overburdened imagination to conclude that salt must have been a major source of wealth at one time, considered worthy enough for a fortress to protect it. That is indeed the case. People have mined the deposits formed by an ancient evaporated sea near Salzburg for at least 3,000 years.

---

Hallein Mine

Some of the salt mines are no longer active but they continue to exist today as museums. The Hallein mine is one of the more accessible and popular, with wooden slides and an underground lake (map). The mineral known at Halite even got its name from this Hallein mine. Most people probably know Halite by a more common designation, rock salt.

Several of the major tunnels at Hallein date to the 15^th Century. Some are even older. Austrian miners dug further and further underground into the hillsides as they followed the lucrative seam of salt. However they found that ancient mineral deposits have no respect for arbitrary modern borders. The Austrians dug first within their own territory but then the salt continued into Bavaria.

---

Reaching the Border

So the nations came to a compromise. In 1829 they negotiated a treaty that allowed the mine to cross the underground boundary. In return, the mine would employ up to ninety Bavarian workers.

Museum visitors today can actually cross the international boundary between Austria and Germany during their tour, a rare example of a legal underground border.