The northwest boundary with Bolivia lies in the Gran Chaco and the Andes Mts. The western boundary with Chile follows the crestline of the Andes. Second in South America only to Brazil in size and population, Argentina is a plain, rising from the Atlantic to the Chilean border and the towering Andes peaks. Argentina is also bordered by Bolivia and Paraguay on the north, and by Uruguay and Brazil on the east. The northern area is the swampy and partly wooded Gran Chaco, bordering on Bolivia and Paraguay.
Next southward is Patagonia, a region of cool, arid steppes with some wooded and fertile sections.
Spanish is the national language, although in Argentina it is spoken in several accents and has absorbed many words from other languages, especially Italian. Numerous foreign languages and dialects can be heard. Lunfardo is now often heard in the lyrics of tango music. There are 17 native languages, including Quechua, Mapuche, Guaran , Tobas and Matacos in Argentina. The vast majority of Argentine people are adherents of Roman Catholicism.