From Cala Gonone, head north on the road to Cala Cartoe until the first sharp hairpin turn (a sharp left turn) where a dirt road continues north from the hairpin turn. Either park here (recommended by the guidebook author because the dirt road is technically closed) or drive the dirt road for about a mile to parking in a dirt pullout on the left. Walk the dirt road until you see a rock on your left with a yellow ying-yang painting that says "millennium cave." Leave the road here heading downhill on a trail that leads to fixed ropes. Continue down the fixed ropes down to the cave.