The main production of what are widely regarded as some of the best olive oils in the world is concentrated in about thirty villages in the comarcas of Les Garrigues (Spain), L'Urgell (Spain) and El Segrià (Spain), along what is often referred to as La Ruta de l'Oli. The rather austere scenary of Les Garrigues, with its own special appeal, provides the perfect backdrop for an outing to buy olive oil and to visit some of the most interesting places in the area. These include its museums and the Olive Oil Theme Park, the castles of Espluga Calba and Floresta as well as El Cogul with its prehistoric cave paintings . It is particularly interesting to visit this area in autumn, when you can see the locally grown olives being processed to make oil at many of the local agricultural cooperatives.