The housing crisis is a European phenomenon, with Barcelona and Catalonia among its most tense areas. It's no surprise, then, that Mayor Collboni traveled to Brussels once again this week to address the issue through the Mayors for Housing alliance, which brings together 17 cities, including Paris, Amsterdam, Lisbon, Milan, and Rome. The mayors' goal is for the European Commission to create an affordable housing fund that would mobilize €300 billion in public and private funds annually.