The Terra Alta Denomination of Origin is the southernmost in Catalonia. It encompasses twelve municipalities from the region of Terra Alta (Gandesa, Corbera, Arnes, Horta de Sant Joan, Vilalba dels Arcs, La Fatarella, Batea, La Pobla de Massaluca, Bot, Caseres, Pinell de Brai and Prat de Comte). The weather of abundant sunshine and little rain, and the little-permeable clays of the land result in powerful wines with high alcohol content. The terrain is varied and the vines are grown in valleys and plains, as well as terraces that take advantage of the area's slopes. In the early 20th century, the vast majority of growers formed agricultural cooperatives to produce their wines. The denomination of origin and its regulatory council were established in 1972, in the town of Gandesa. Reds are produced from maçola, white grenache and “hairy” grenache varieties; and whites, with white grenache and macabeo. They also make dry and sweet wines, particularly vi ranci, which must age in oak barrels for five years. The wines of the Terra Alta Denomination of Origin are characterised, as far as whites are concerned, by being fresh and balanced; rosés are fruity, while reds are stronger, with an intense ruby colour. Dessert wines here tend to be quite sweet. In Gandesa gastronomic events are organised at the end of October, which include a wine festival that has been held since 1987. It includes talks, a wine sample, speed courses in tastings and a community lunch. Gandesa is also home to the Espai del Vi i de l'Oli, an interpretation centre for the wine and olive oil of Terra Alta, which hosts exhibitions, courses, talks and debates throughout the year. The town is also the starting point for the Wine Route. This route through the region’s wine-producing centres winds its way through fields of vineyards where you can see the marges, dry stone constructions that delimit slopes and terraces, a veritable symbol of the work of winegrowers. In Pinell de Brai there is an Art Nouveau winery, work by César Martinell. The façade has a ceramic frieze of stained glass by Xavier Nogués, with allegorical scenes of vineyards and wine.