This chapter presents Republican-era efforts to turn the Yangtze River into an engine of developmental nation-building by erecting a Three Gorges Dam. Starting with Sun Yat-sen’s initial proposal in 1919 and closing with the Sino-American attempt in the 1940s, this chapter examines how Chinese and foreign actors pursued this developmental dream.Undeterred by the financial challenges of the project, the dam’s backers argued China could overcome a domestic dearth of capital by working with foreign collaborators. This joint venture would benefit both China and foreigners by not only easing trade with the Chinese interior and creating a marvel of modern engineering, but also because the dam would furnish a gargantuan electrical stimulus to the transformation of China into an industrial powerhouse with a growing demand for foreign products. Although the dam was not constructed in the Republican period, Chinese and foreign actors would continue to pursue the infrastructural fantasy of installing mammoth dams on China’s rivers to fuel national industrialization on both sides of the Taiwan Straits during the Cold War.