@garfieldairlines Interestingly, there are lots of places with "Loch" (hole / trou) or Löchli (diminutive, small hole) here. Usually it's a steep valley of sorts, in this case I think it's a cave, I only saw the signpost (and my mobile phone failed to take a picture, even though I pushed the button, multiple times).
Anus also sounds a fun place to visit, unfortunately it is too far away for a bike tour :(