This article describes and analyzes a cross-border, "simultaneous exhibition" collaborative project in six post-conflict western Balkan countries. Through a process of collaboration, active learning, and audience development, professional and personal trust developed among eleven museums. Previously identified barriers were overcome and expectations of the original project were surpassed leading to a shared joint-platform, visible collaboration, and an international profile. The case study provides a model for museum collaboration and trust-building among different organisations.