One Planet City. A Call from Guimarães to the World.
We, the cities, stand on the frontlines of the climate emergency. In our neighbourhoods, schools, businesses, and communities, the future of the planet will be decided. Here lies both our greatest challenge and our greatest opportunity.

We believe that cities can accelerate the global transformation towards sustainability, justice, and resilience. We also believe that innovation, creativity, and community are our most powerful resources. By fostering more engaged and informed communities, strengthening the preparedness of teams, and shaping
territories that are better adapted, we build lasting resilience in the face of future
challenges.

Therefore, we declare:
→ Education must be the foundation of sustainable societies. Knowledge changes the world.
→ Science must guide every action. Evidence and open data are our compass.
→ Just Transition must leave no one behind. Social justice and climate action are inseparable.
→ Innovation in business, industry, and the broader economy is important for advancing the
green transition, demonstrating that prosperity and sustainability go hand in hand.
→ Sports and Culture must inspire change. Celebration, creativity, and movement are
catalysts for transformation.

We commit to act locally and inspire globally — each city taking at least one of these
pillars as a measurable commitment. From Guimarães, European Green Capital
2026, to the world: we invite cities everywhere to join this journey. Together, we
will prove that sustainable futures are built from the ground up, through courage,
innovation, and collaboration. One Planet, One City. Our shared future starts here.