The Soleleitung, dating from the early 17th century, is the oldest industrial pipeline in the world. During construction, from 1597 to 1607, 13,000 spruce and fir tree trunks were used form a 40 kilometre long pipeline to convey brine from the salt works Hallstatt to Ebensee where it was refined and taken by barge to Gmunden. This method of conveyance superseded the excavation of salt rock and transport overland. The pipeline starts at the Rudolfsturm and the walk along its route takes in some of the most spectacular views of the Salzkammergut.