Since ancient times, humans have sought distant places to settle, produce, and exchange goods enabled by improvements in technology and transportation. But not until the 19th century did global integration take off. Following centuries of European colonization and trade activity, that first “wave” of globalization was propelled by steamships, railroads, the telegraph, and other breakthroughs, and also by increasing economic cooperation among countries. The globalization trend eventually waned and crashed in the catastrophe of World War I, followed by postwar protectionism, the Great Depression, and World War II. After World War II in the mid-1940s, the United States led efforts to revive international trade and investment under negotiated ground rules, starting a second wave of globalization, which remains ongoing, though buffeted by periodic downturns and mounting political scrutiny.