The public track eventually fizzles out at Estancia María Luisa, 18km further on, just beyond which run the famous fishing rivers, Irigoyen and Malengüeña. This is the beginning of the Península Mitre, the bleak toe of land that forms the southeastern extremity of Tierra del Fuego. This semi-wilderness – primarily swampy moorland and thickets fringed by rugged coastal scenery – was once the territory of the indigenous Mannekenk, whose presence is attested to by old shell middens. Before the 1850s, the only white men who came ashore were sailors and scientists, such as Fitz Roy and Darwin, as well as shipwreck victims; the remains of many wrecks line the shore, including the late nineteenth-century Duchess of Albany, near Bahía Policarpo. Apart from a few gauchos, the peninsula is now effectively uninhabited, and the only way to explore the area is on guided horseriding excursions with Centro Hípico Ushuaia (Ruta 3, west of town; t02901 1556 8278, wwww.horseridingtierradelfuego.com), which runs trips down the Costa de los Naufragios, from Estancia María Luisa to Estancia Policarpo and back.