Abstract
This article analyzes the relationship between the internal development capacity of a region and the establishment of external infrastructures which link various centres and create cohesive spaces. The methodological approach is based on two types of network (1) internal networks (INs) bring together a wide range of economic and institutional agents; (2) external networks of infrastructures (ENs) show an increasingly international orientation and accompany the spatial dynamic. The theoretical approximation serves as a starting point for the study of some important projects the aim of which is the diffusion of ENs in the Basque country (roads, railways, airports and telecommunications). These projects are occasionally connected with the dynamics of INs that tend to be set up in the metropolitan area of Bilbao.