grotta di frasassi, genga, italy. lake in the cave, stalactites and stalagmites closeup

cave formation quail caving stalagmite stalactite geology tunnel wadi person canyon ice painting rock darkness terrain infrastructure grotta frasassi genga italy inside one most extensive caves lake stalactites stalagmites closeup europe nature stone cavern landmark famous park excursion guide indoors spooky background natural dark lights travel underground landscape mountain wall light tourism limestone rocks grotto ancient tree water italy