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

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