The conceptual pair of “visibility/concealment” is foundational to the field of animal studies and the animal advocacy movement, substantiating the idea that uncovering violence against non-human animals in factory farms and slaughterhouses can lead to its eradication. This perspective and consequent activist strategies fall under the scopes of “the politics of sight”. This chapter, first, challenges on a theoretical level the equation between vision and truth underpinning the politics of sight by succinctly outlining a materialist approach for the critique of violence in which the Foucauldian notion of apparatus (dispositif), as a network of practices and knowledges, plays a crucial role. Second, the relevance of sight is further challenged on a historical basis. Analysing the knowledges involved in the rise of the modern industrial slaughterhouse in the nineteenth-century West, this chapter shows the primacy of miasmatic theory and, thus, smell. On the other side, sight emerges as a main element in the moralizing, utilitarian, anthropocentric and classist, narrative of the early animal advocacy associations. Finally, the chapter briefly examines as a case-study the slaughterhouse tours both in nineteenth century and contemporary settings (e.g., transparency campaign by meat industry) in which the equation between violence and visibility/concealment stand in a highly problematic level.