a small tunnel on the footpath above the reservoir lake lago di lucendro or in the swiss alpine area of the st. gotthard pass

abandoned airolo alpine area background black canton cave cavern coal construction copper corridor dark dig dirt dirty energy engineering entrance excavate explore footpath geology gold gotthard gotthardpass hard historical indoor industrial industry inside interior iron lago lake light lucendro machinery metal mine mineral old pass path pit railroad reservoir rock safety schweiz shaft silver small spooky stone swiss switzerland tessin ticino tool tunnel tunneling underground underpass way work