Using a transnational perspective, the paper argues that the transformation of the Avenue of the Americas must be understood in relation to the growing involvement of leading New York reformers in Latin America, especially São Paulo. Specifically, the paper illustrates how New York urban reformers’ perception of São Paulo as a rising city (and thus a potential rival) and that of Brazil (and Latin America) as important allies to the United States served as catalysts for further growth in New York as these actors – especially Robert Moses and Nelson Rockefeller – strove to maintain the city’s global dominance. By focusing on the networks of exchange between São Paulo and New York, and taking seriously the multidirectional flows of influence between these two cities, this paper sheds fresh light on the ideological origins of New York’s urban renewal projects while not losing sight of how average New Yorkers responded to elite visions of the city.