This paper studies the role of leaders in the social movement against slavery that culminated in the US Civil War. Our analysis is organized around a natural experiment: leaders of the failed German revolution of 1848–1849 were expelled to the United States and became antislavery campaigners who helped mobilize Union Army volunteers. Towns where Forty-Eighters settled show two-thirds higher Union Army enlistments. Their influence worked through local newspapers and social clubs. Going beyond enlistment decisions, Forty-Eighters reduced their companies’ desertion rate during the war. In the long run, Forty-Eighter towns were more likely to form a local chapter of the NAACP.

We study the impact of large, successful manufacturing plants on other local producers in China, focusing on “Million-Rouble Plants” built in the 1950s during a brief alliance with the U.S.S.R. The ephemeral geopolitical situation and the locations of allied and enemy airbases provide exogenous variation in plant siting. We find a boom-and-bust pattern: Counties hosting these plants were 80% more productive than control counties in 1982 but 20% less productive by 2010. This decline reflects the performance of local establishments, which exhibit low productivity, limited innovation, and high markup. Specialization hindered spillovers, preventing the emergence of new clusters and local entrepreneurship.

Why are the east sides of formerly industrial cities more deprived? To answer this question, we use individual-level census data and create historical pollution patterns derived from the locations of 5,000 industrial chimneys and an atmospheric model. We show that this observation results from path-dependent neighborhood sorting that began during the Industrial Revolution, as prevailing winds blew pollution eastward. Past pollution explains up to 20% of observed neighborhood segregation in 2011, even though coal pollution stopped in the 1970s. We develop a quantitative model to identify the role of neighborhood effects and relocation rigidities underlying this persistence.

Using newly constructed spatially disaggregated data for London from 1801 to 1921, we show that the invention of the steam railway led to the first large-scale separation of workplace and residence. We show that a class of quantitative urban models is remarkably successful in explaining this reorganization of economic activity. We structurally estimate one of the models in this class and find substantial agglomeration forces in both production and residence. In counterfactuals, we find that removing the whole railway network reduces the population and the value of land and buildings in London by up to 51.5% and 53.3% respectively, and decreases net commuting into the historical center of London by more than 300,000 workers.

This paper analyzes the effects on voting behavior of information disseminated over the Internet. We address endogeneity in Internet availability by exploiting regional and technological peculiarities of the preexisting voice telephony network that hindered the roll-out of fixed-line infrastructure for high-speed Internet. We find negative effects of Internet availability on voter turnout, which we relate to a crowding-out of TV consumption and increased entertainment consumption. We find no evidence that the Internet systematically benefits specific parties, suggesting ideological self-segregation in online information consumption. Robustness tests, including placebo estimations from the pre-Internet period, support a causal interpretation of our results.