"Barcelona from Within" is a cooperative scavenger hunt that allows participants to explore the social and environmental challenges of the Old City while solving puzzles and team challenges. The activity combines urban exploration, interaction with social organizations, and visits to community spaces. During the game, participants must help journalist Mercè J. reconstruct an encrypted article to transform Barcelona into a fairer and more sustainable city. The dynamic encourages reflection on gentrification, social economy, and climate change, and includes a donation to a partner organization.