The 1990s marked the beginning of a new era in world history. The Cold War was over, new human rights initiatives were springing up in long-repressed countries, and the so-called age of globalization was under way. By the early twenty-first century, the political and economic systems of all countries were more intricately linked and interdependent than ever before. Booms and busts, environmental issues, terrorism, war, and the spread of multinational corporations had become concerns for all nation-states. The United Nations emerged as an important voice in the global political arena. Western corporations reached into developing nations promising economic improvement on the one hand, and seeking new and cheaper sources of labor on the other. For some, the global economy has led to growth, technological development, and the promise of social and political reform. For others, the greater worldwide interconnectedness has exposed vast differences in values and wealth. One international constant remains — the struggle of people to be responsible global citizens.