After 1960, museums found themselves repeatedly challenged for the borders they had placed in society around race, gender, class, and so on. New ethical borders erupted in the landscape of knowledge. This chapter examines the nature of these borders by attending to the admission of black artists into the Museum of Modern Art (MoMA) in New York. This was part of a larger ‘multicultural’ debate in art history that extended to World Art Studies. The chapter argues that ideas of change described in various ‘turns’ are better articulated in the language and concepts of borders where they can be understood as incomplete and liminal. The border zone does not articulate a simple binary opposition but a complex of competing and changing positions. The chapter ends by examining the reimagined MoMA of 2019, which seemed at last to embrace changes it had known were necessary some 50 years earlier. It had been ethically rebordered.