This card shows a beautiful place near Monte Argentario in Tuscany, Italy. I couldn't find much information about Costa D'Argento itself, but reading about the geography of Monte Argentario you can easily notice that it's interesting :)
Monte Argentario is a promontory stretching towards the Tyrrhenian Sea in correspondence of the two southernmost islands of the Tuscan Archipelago, Giglio and Giannutri. The promontory was also an island in past times,, but the sea currents and the Albegna river joined it with the mainland through two so-called tomboli (stretches of land), The Tombolo of Giannella and the Tombolo of the Feniglia.The highest peak of Monte Argentario is the Punta Telegrafo (635 m). The landscape and the coast are mainly rocky; numerous harbors, usually with rock beaches, are present. The municipal seat is in the northern settlement, Porto Santo Stefano.