Spain is a nation with high mountain ranges and plateaus such as the Sierra Nevada and Pyrenees dominated mainland Spain. It is home for many rivers running from the mountain heights like the Guadalquivir, the Tagus, the Duero, and Ebro. To the offshore of the Mediterranean lie the Balearic Islands and the self-governing Canary Islands can be seen off the African coast. Spain is a constitutional monarchy, with a hereditary monarch and a parliament with two chambers: the Cortes. Linguistic and cultural diversity was valued in 1978 constitution. The nation has 17 autonomous communities (regions) which all have their own directly elected authorities. Communities like Galicia, the Basque, and Catalonia, the regional languages have official status alongside the national Spanish language.