Pomarance is historically important for the development and the exploitation of geothermal energy in the district of Larderello, so called in honour of the French engineer François Jacques de Larderel of the XIX century who promoted its exploitation. Larderello, that rose under an extraordinary economic expansion, is compared, by the critics of the time, to a small town of the "West", for the almost pioneering nature of the operation. Surrounded by the green and weaved by a plot of walking routes, it is linked to the industrial park by a hillside road. The infinite variety of glimpes and views, offered by the numerous solutions of the arrangement of the urban space, suggests a cozy and intimate dimension of the village that appears almost extraneous to the reality that surrounds it, even though the reason for its very own origin resides in this reality; in this way, in spite of the vicinity of the factories it is almost like there aren't any of them. Moderate and at the same time detached from the underlying "metaphysical" landscape, crossed by a suspended lattice of silver tubes and marked by the enormous volumes of the refrigerators, the village inserts itself in the environment without physically subverting it, rather adding a touch of warm humanity to it. The place name of Pomarance was documented for the first time in 1128 as Ripomarrancia. While the first element of the name is the Latin word ripa (bank), the second one is more uncertain and it could derive from the Roman person's name Arranciae (maybe of Etruscan origin). Yet, the place name could derive from the ancient Italian pomarancia, that means apple-orange. Libbiano is one the smallest districts of Pomarance municipality. Together with Micciano and Serrazzano, other districts of Pomarance, it shares one of the most important forests of the province of Pisa: the Natural Reserve of Monterufoli-Caselli. Always in the nearby area there is the district of Lustignano, medieval hamlet that rises on the slopes of the river Cornia. Do not miss the panorama from the Rocca Sillana (Silana or di Sillano), a powerful fortress that dates back to the XII century. The Rocca majestically dominates on the summit of a hill elevation at 530 metres above the sea level, in a privileged position from a military point of view. Indeed, the Rocca allows to strategically control the Val di Cecina and the related valleys, a very extended territory that includes wide portions of the province of Pisa, Siena and Grosseto. The legend, also by virtue of its name, tells that the origin of the fortalice would derive from the civil war between Mario and Silla. According to this legendary theory, the name of the Rocca Sillana would ideed derive from the last name of the Roman general Lucio Cornelio Silla.