The Island of Zannone belongs to the Pontine Islands archipelago, together with Ventotene, Ponza, Palmarola, Santo Stefano and Gavi. It is the northernmost island, and only the third to last in size (103 hectares, or 0.9 square km).
Zannone is the only Pontine island to be made, as well as of volcanic rocks, of metamorphic and sedimentary rocks dating back to over 200 million years ago.
Thanks to its naturalistic importance, it was incorporated into Circeo National Park in 1979, thus becoming its insular appendage.
Although small in size, Zannone is home to interesting endemic plant and animal species, preserved throughout the centuries thanks to man's scarce presence.
Human settlements on the island date back to prehistory, and great civilisations, such as the Romans, were there; but no one has ever stayed long, because of docking difficulties or - as was the case with the Benedictine-Cistercian monks who settled at Convento di Santo Spirito in the XII century - because of continual pirate incursions.
Unlike the other islands in the Archipelago, jagged and barren, Zannone is evenly shaped, compact, and has a lush and well preserved Mediterranean vegetation, therefore representing an ideal rest stop for thousands of migratory birds.