Over the past two centuries, federal, state and municipal governments across the United States have launched wave after wave of infrastructure projects. They built canals to move freight in the 1830s and 1840s. Governments subsidized railroads in the mid- and late 19th century. They created local sewage and water systems in the late 19th and early 20th centuries, and then dams and irrigation systems through much of the 20th century. During World War II, massive amounts of public money were spent building and expanding ports, factories, airfields and shipyards. And after the war, highway construction — long a state and local project — became a federal endeavor.