World War I marked a turning point for the United States as millions of American “doughboys” traveled overseas to fight in Europe. Experiencing trench warfare, modern industrial combat, and foreign cultures for the first time, these soldiers helped transform America into a global power. The war changed not only international politics, but also how Americans understood their nation’s role in the world and their own identity within it.

During the Progressive Era, Theodore Roosevelt led efforts to regulate powerful monopolies, protect consumers, and preserve natural resources. By enforcing antitrust laws and responding to public concerns about unsafe industries, his administration expanded the role of government in maintaining fairness. This period marked a turning point in American history, as the nation began to balance industrial growth with social responsibility.

The Panama Canal was a transformative engineering project that connected the Atlantic and Pacific Oceans, reshaping global trade and naval power. After a failed French attempt, the United States successfully completed the canal by overcoming major challenges, including disease and difficult terrain. Opened in 1914, the canal symbolized American technological capability and growing global influence, while also raising questions about power and intervention abroad.