The Marche region offers areas of natural beauty: the splendid Monti Sibillini feature in some places Alpine landscapes; the spectacular Frasassi caves; and the forest-clad mountains in the Montefeltro area, forming a backdrop to craggy spurs. The most magnificent mountain landscapes in the Marche are to be found in the Monti Sibillini National Park, which is about 40km (25 miles) in length and extends into Umbria. From the summits of Monte Vettore (2,476 m), Monte Sibilla and Monte Priora – described by the poet Giacomo Leopardi as the “blue mountains” – to the valley of the Fiastrone and the Gole dell’Infernaccio, nature is combined with the legends of the Sibyl, a soothsayer who was said to have lived in a cave on Monte Sibilla, Guerrin Meschino (a character from the Carolingian epic) and Pontius Pilate, after whom the only natural lake in the Marche (Lago di Pilato, high up on Monte Vettore) is named. And at the foot of the mountains there are numerous towns and villages, boasting remarkable churches and interesting museums. A small part of the Marche, comprising the municipalities of Acquasanta Terme and Arquata del Tronto, lies within the borders of the Gran Sasso and Monti della Laga National Park. On the border with Tuscany, the Interregional Park of Sasso Simone and Simoncello, in the Montefeltro area, is well known for the large beechwood of Pianacquadio. In the 16th century, on the rock of Sasso Simone, the Medici built a fortified town that was later abandoned because it was not easily accessible. There are many areas of outstanding natural beauty in the province of Pesaro and Urbino, such as the Cesane pine wood between Urbino and Fossombrone. Not far away are the massif of the Furlo, with its suggestive gorge, recently recognized as a national nature reserve; the Alpe della Luna, after Mercatello sul Metauro; and the area of Monte Catria and Monte Nerone, with its many gorges and natural arches. The province of Ancona also boasts the Gola Rossa and Frasassi Regional Park, with many rocky areas crossed by the two gorges of the same name, the habitat of golden eagles, peregrine falcons, and eagle owls. Near Fabriano is the Centre of Environmental Education of Valleremita. Worth seeing in the province of Macerata are the Monte San Vicino with the ancient beechwoods of Canfaito, now a natural reserve; the maquis of Montenero in Cingoli and the valley of the Grilli that ends in the S. Eustachio Gorge, which is surrounded by the caves of the same name. Between the municipalities of Pieve Torina and Monte Cavallo, at the foot of the Monti Sibillini, is the Montagna di Torricchio Nature Reserve, recognized as a biogenetic reserve by the European Council. The Cistercian abbey of Chiaravalle di Fiastra is included in the other nature reserve, Abbadia di Fiastra, renowned for its agricultural landscape. The abbey has well preserved its medieval layout. In winter  many small villages become nativity scene locations. The snow-capped peaks welcome adults and children on the ski slopes, snow parks, and refuges. The main ski resorts are: Piani di Ragnolo (Acquacanina), Monte Prata (Castelsantangelo sul Nera), Pintura di Bolognola (Bolognola), Sarnano–Sassotetto (Sarnano), Frontignano di Ussita (Ussita), Forca Canapine on Monti Sibillini, Monte Piselli in the Gran Sasso and Monti della Laga National Park, Monte Catria in the province of Pesaro e Urbino, Montecopiolo with two ski resorts in the Sasso Simone Simoncello Park area, Monte Nerone in the province of Pesaro e Urbino.