huel lee or hohllay on the mullerthal trail in luxembourg, open cave with view to the forest, sandstone rock formation

aesbech ardennes autumn basalt berdorf canyon cave den echternach erosion europe forest formation geology gorges green hiking hohllay hole huel landscape lee loup luxembourg luxembourgish moss mountain mullerthal natural nature open outdoors path perekop rock rocks sandstone stone summer swiss switzerland toursim trail travel tree trees valley view wall wolfschlucht wood woodland