The building of human towers (castells) is a centuries-old competitive practice where hundreds of men, women, and children gather in Catalan squares to create breathtaking edifices through a feat of collective athleticism. The result is a great spectacle of suffering and overcoming, tension and release. Catalonia's Human Towers is an ethnographic look at the thriving castells practice-a symbol of Catalan cultural heritage and identity amid debates around autonomy versus subsummation by the Spanish state. While the main function of building castells is to grow community through a low-cost, intergenerational, and inclusive leisure activity, Mariann Vaczi reveals that this unique sport also provides a social base, image, and vocabulary for the pro-independence movement. Highlighting the intersection of folklore, performance, and self-determination, Catalonia's Human Towers captures the subtle and unconscious processes by which the body becomes politicized and ideology becomes embodied, with all the risks and precarities of collective constructions.