Val d’Orcia, a Renaissance Agricultural Landscape
Val d’Orcia is the valley formed by the river Orcia in the southern part of Tuscany, in the Province of Siena, on the border with Latium. The river springs from a gorge on Mount Cetona, winds its way approximately northwestward crossing the municipalities of Cetona, Sarteano, Pienza, San Quirico d’Orcia, Castiglione d’Orcia and Montalcino, and is then tributary to the river Ombrone (in the Province of Grosseto) flowing toward the Tyrrhenian Sea. Thus, the valley runs between the hills south of Siena and the ancient extinct volcanic masses of Monte Amiata (1,738 m) and Radicofani. The geological form of the area was determined 5 million years before the present when the sea receded, leaving behind the sand and clay deposits that formed the valley surface. Later, the two volcanoes (the northernmost of a long line of extinct, dormant, or still active volcanoes on the Tyrrhenian side of Italy) covered the soil with erupted lava that, when it cooled, became a rock known as trachyte.