Chapter 21 of Earthopolis: A Biography of Our Urban Planet begins a four-chapter segment on the Greatest Acceleration, the sheer explosion of cities that began after 1945 and picked up at an even greater pace after 1980, resulting in the first megacities and several enormous contiguously urbanized regions. It surveys the vast built realm of Cold War-era imperialism and the increasingly centralized power of global finance capital to clarify the changing political economic conditions – first driven by ideologies of plenty, then “austerity” – under which the Acceleration took place. It also begins to explore the global development work of post-War imperial states, multilateral organizations and corporate foundations, focusing on transformations of public health infrastructure and of “Green Revolution” agricultural environments. All of these were crucial to the broader explosion of global population, the growing immiseration of the rural poor, and the city-ward migration that undergirded the Acceleration.