Inside this cave are the bones of a deer that no longer exists. It is the Sardinian megaceros, a relative of the giant deer of the European steppes which, isolated on the island, shrank over the generations until it became a dwarf deer. The fossil deposit was found in 1995, during an exploratory dive.
What to see
The cave opens in the karst complex of punta Giglio, a few kilometres north-west of Alghero, and is set out on three levels. At first they simply called it the cave of punta Giglio; then it was named after the diver who had explored it, and in the end the name its deer gave it prevailed.
It is worth pausing on what it means to find deer bones in a cave that is now underwater. When those animals were alive the sea stood much lower, the cave was dry and you walked into it. Then the ice melted, the water rose and sealed everything: that is why the remains have been preserved.
Visiting
It can be reached only by diving, with a diving centre and the right certification; the site is inside a protected area and the fossils are not to be touched or collected. Half a day with the boat trip.
Our editors' tip
If you do not dive, climb the headland of punta Giglio, which can be walked or cycled through the scrub and the military posts of the second world war. Get to the edge and look down: under that water is the cave, and inside the cave is an animal that made itself small in order to survive an island.