Andean natural region
The Andes mountains form the most populated region of Colombia and contain the majority of the country's urban centers. They were also the location of the most significant pre-Columbian indigenous settlements. Beyond the Colombian Massif in the south-western departments of Cauca and Nariño, the Colombian Andes divide into three branches known as "cordilleras" (from the Spanish for "mountain range"): the West Andes run adjacent to the Pacific coast and is home to the city of Cali. The Central Andes run up the center of the country between the Cauca and Magdalena river valleys (to the west and east respectively) and includes the cities of Medellín, Manizales and Pereira. The East Andes extend northeast towards the Guajira Peninsula, and includes the cities of Bogotá, Bucaramanga and Cúcuta.
Vertical archipelago
Absent the use of trade to access resources, economic transactions were essentially intra-lineage obligations of labor. These lineages required a base level of self-sufficiency to achieve autarky. In the Andes, a long mountain range with a great variety of ecozones and resources, the need to access the proper lands for specific crops or animals meant lineages created miniature colonies or sent seasonal migration (such as transhumance) in different ecoregions. As the Andes are a relatively young mountain range, there is an especially great variation in rainfall and temperature, which has great importance for agriculture. This is all the more important as only about 2% of the land in the Andes is arable.