America Usa

Driven by the doctrine of Manifest Destiny, the United States embarked on a vigorous expansion across North America throughout the 19th century.[23] This involved displacing American Indian tribes, acquiring new territories, and gradually admitting new states, until by 1848 the nation spanned the continent.[23] During the second half of the 19th century, the American Civil War ended legal slavery in the country.[24][25] By the end of that century, the United States extended into the Pacific Ocean,[26] and its economy, driven in large part by the Industrial Revolution, began to soar.[27] The Spanish–American War and World War I confirmed the country's status as a global military power. The United States emerged from World War II as a global superpower, the first country to develop nuclear weapons, the only country to use them in warfare, and a permanent member of the United Nations Security Council. The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the world's sole superpower.[28]

The United States is a developed country and has the world's largest economy by nominal and real GDP, benefiting from an abundance of natural resources and high worker productivity.[29] While the U.S. economy is considered post-industrial, the country continues to be one of the world's largest manufacturers.[30] Accounting for 34% of global military spending[31] and 23% of world GDP,[32] it is the world's foremost economic and military power, a prominent political and cultural force, and a leader in scientific research and technological innovations.[33]

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