This book offers an unprecedented exploration of Greece's immigration detention system, uncovering its hidden histories, systemic violence, and the struggles of those confined within its walls. Drawing on over a decade of ethnographic research and personal experience as an NGO practitioner, it exposes how detention has been used as a tool for border control, racial exclusion, and social punishment. The book traces the evolution of Greece's detention system, from its roots in the 1990s through the so-called refugee crisis of 2015 to the present, connecting these practices to broader European border policies. Through vivid stories from detained people, activists, and practitioners, the book documents acts of resistance inside detention centres and the solidarity movements that support them. It highlights how state institutions, including the police and NGOs, sustain and legitimize violence under the guise of humanitarianism and security. Engaging with abolitionist thought, the book challenges the inevitability of detention, calling for a future without cages. It will resonate with readers interested in migration, social justice, and human rights, offering a vital contribution to contemporary debates on borders, confinement, and resistance across Europe and beyond.