Sixth community in extension, 6,3 % of the Spanish territory and the second most populated, with 15,6 % for what the first positions occupies in population density. The industrialization of the zone has done that to the natural growth is necessary to add the great immigration, principally in the sixties and beginning of the seventies. In the 13th century, under the Hispanic Mark authority the Autonomous government of Catalonia is created, inside the Catalan Spanish Parliament, being promulgated the first civil laws. In the Low Middle Ages it joins the Wreath of Aragon, the trade being stimulated by the Mediterranean and the emergence of the middle class, sat down the bases of an industrial development. The Catalan language is previous to the political institutions. The first written texts, of religious character, go back to the 10th century.

They alternate the mountain landscapes (Pyrenees and Coastal - Catalan Mountain chain), the interior plains and the littoral. The Aigües Tortes's national Park and Lake San Mauricio (1.957) stand out in the Pyrenees, importantly for its quaternary glacierism. In the interior plains Montserrat's mountain range stands out with strong differences, composed by conglomerates, which hardness stands out in the middle of the landscape, though with some showy fractures.

The units of relief arise with the Alpine orogenia. The following ones can be distinguised:

Catalan Pyrenees: it spreads from the Monte Perdido and the Maladeta up to Creus's Cape, where it is possible to distinguish the axial zone and the pre- Pyrenee is limy. Higher summits are in the bordering zone with Aragon.

The Central Depression crossed by the river Ebro in its North-East sector

The Coastal - Catalan Mountain chains, in the north zone predominance of granitic and slaty materials of paleozoic origin, whereas in the south zone they predominate over limy mesozoic sediments. The interior zone reaches heights of 1.500 m and in the littoral of 200 m.

To mention the Transverse Catalan Mountain chain, which joins the Pyrenees with the coastal - Catalan Mountain chain, its reliefs close for the North-East the Ebro Depression coming up to the gulf of Roses, and the coastal plains that include the delta of the Ebro and of the Llobregat.

High Earths of the Pre- Pyrenees, with rainfalls over the 600 mm/year. In this zone the basin of the Segre is the one that has a drier summer.

Mediterranean with oceanic influence, with a maximum of rainfalls in the equinoxes and risk of torrential rains in autumn. A dry and warm summer and a winter with soft temperatures in general.

Continental Mediterranean in the Central Depression, which is most accused in the western zones. Of minor rainfalls, in any areas they do not come to the 300 mm/year. The thermal daily and annual extent is marked.

Mountain, which it is possible to define like Alpinly and subAlpinly, is characterized by a bigger quantity of rainfalls, regularly distributed the whole year and in occasions in the snow shape.

It changes depending on the relief units :

Pyrenees zone : it begins with the grove of evergreen oaks followed by the oak with scots pines, sometimes the black pine appears in height, alternating with beeches in more humid or colder zones. In bigger heights we enter the fir and the top meadows and perpetual snow.

In the Littoral, the oak forest is very degraded by the repopulation with pines very adapted to the drought and stone pines, on Silica soils the blockhead.

In the Central Depression the forest is absent and it gives the bushes with thyme, lavender, etc up to connecting with the Aragonese steppe.

The rivers cut transversely the mountains in E-O, NE and SO direction , facilitating the communications among the regions. The Pyrenean rivers are short, save big unevennesses and are taken advantage for the obtaining of hydroelectric energy. Among the Pyrenean rivers we can emphasize the Fluviá, Ter, Llobregat, etc, among the properly Mediterranean ones there are the Congost and Mogent, which contribute its waters in the Besós, and the Francolí, without forgetting the river Ebro that ends on the Catalan coast after crossing several Autonomies.