Our ultimate goal is the Kaiser Wilhelm tunnel, with a length of 4 km. The longest of all tunnels we explored was the tunnels of Veurs. In order to discover the border between fun and too long we decided to pick a tunnel with an intermediate length. It became the Rudersdorfer tunnel. It is a nice tunnel, but it is long indeed. It was a great adventure. I'll tell the story in the fotoreportage section.
The tunnel was build in 1915, further there is no historical information.