The fourth edition of the City and Science Biennial took place simultaneously in Barcelona and Madrid, between November 18 and 23, 2025. And it was also extended with a special edition of science programming within the framework of the Guadalajara International Book Fair, held between November 29 and December 7, 2025.

In the third edition of the Biennial, Madrid joins Barcelona, ​​and the two cities bring together more than a hundred programmed activities. The meeting explored a science that relates human beings, nature and technology, and vindicates the idea of ​​living and coexisting. A science that offers opportunities for a more sustainable model of life.

The second Biennale focused on the concept of limits and brought together a total of 138 speakers from the world of research, outreach, thought and the arts who, together with the public, reflected openly on knowledge and to be able to explore science in all its dimensions.

In its first edition, with a hundred activities and 125 invited people, the Biennale reflected on how science can help solve our concerns, how to make scientific knowledge accessible and achieve citizen involvement, what dilemmas arise of the relationship between science, the market and public authorities, and how we can ensure that everything that is publicly invested in science serves progress and social transformation.