Ustica Gold Cave is located north of the island, in zone C of the Ustica Island Protected Marine Area, and owes its name to a yellowish color in the volcanites where burgundy red predominates. It is a cavern dug by the waves in an explosive breach with many sharp-edged boulders included that constitute a reason for danger as they are about to fall at any moment. You can enter the cave comfortably by boat even with undertow through the entrance about ten meters wide, a little less high on the surface of the water and from this to the bottom, covered with large pebbles, about 6 meters. The cave is entirely marine, with no beach and no landings, formed by a single environment that develops for about fifty meters with rather sinuous walls, with several arched grooves, the largest of which, at about twenty meters in the right wall, can accommodate some boats. The wall facing it for several meters has no supports in the seabed, and a glimmer of light penetrates from the edges immersed in the water. The first forty meters of the development maintain a rather constant width, of about ten meters like the entrance, then it suddenly narrows to about 4 meters and continues for another ten meters ending at cul-de-sac. The elevation of the bottom of the cave, strewn with large pebbles, is slightly uphill; it is estimated about 5 m at the entrance, 3 m at about twenty meters, a couple of meters at about 35 m, in the next terminal section a slightly lower depth. The height of the vault from the surface of the sea is about 8 m at the entrance, in the central part at 20-30 m it is estimated about ten meters with ups and downs, then a few meters from the bottom 4 meters to go up a couple of meters at the end of the tunnel.