The first cities to symbolically endorse the Basque Declaration were Bilbao, San Sebastian and Vitoria, followed by dozens of representatives from local European governments attending the conference.

The Declaration, which was preceded by the Aalborg Charter (1994) and the Aalborg Commitments (2004), aims to lay the foundations of the path to the sustainability of cities and towns, recognising that an inevitable "technological, socio-economic and socio-cultural transformation” will be required to do so.

Its goal is to create "productive, sustainable and resilient towns and cities", where the quality of life of citizens is assured, but in such a way as to "respect the boundaries of the local and global ecosystems and natural resources available".