United States of America

To the United States of America is a federal constitutional republic comprising fifty states and the Federal District. Most of the country in the middle of North America, where the 48 states and Washington, DC between the Pacific and the Atlantic Ocean and is bordered by Canada to the north and Mexico to the south. The state of Alaska in the north-west of the continent, bordered by Canada's east and Russia to the west across the Bering Strait. The state of Hawaii, a group of islands located in the middle of the Pacific. It also includes many state of the land, or islands in the Caribbean and the Pacific.

The United States came in third or fourth in terms of area 3.79 million square miles or 9.83 million km 2), and ranks third in terms of population density is 307 million people and is characterized by the United States as one of the world's most diversified in terms of race and culture, came as a result of migration large it from different countries and U.S. economy is the largest national economy in the world, with an estimated GDP for 2008 estimated at $ 14.3 trillion U.S. (23 per cent of the global total, based on nominal GDP and almost 21% in terms of purchasing power

The nation was founded by thirteen British colonies along the coast of the Atlantic Ocean. They issued the Declaration of Independence on the Fourth of July 1776, which recognized their independence from Great Britain and the formation of a federal government. Rebellious states defeated Great Britain in the American Revolutionary War, the first successful colonial war of independence. [9] The Philadelphia Convention adopted the current United States Constitution, on the seventeenth of the month of September 1787; and ratified the following year made the states part of the Republic that has a strong central government. As the ratification of the Bill of Rights in 1791, comprising ten constitutional amendments guaranteeing many fundamental civil rights and freedoms.

In the nineteenth century, the United States acquired land from France, Spain, the United Kingdom, Mexico, Russia, and annexed the Republic of Texas and Hawaii. Disputes between the agricultural South and industrial North over states rights and the expansion of the slave trade to the outbreak of the American Civil War in 1860 approx. Prevent the victory of the northern region a split in the country, which led to the end of legal slavery in the United States. The national economy has become the largest economy in the world by the year 1870 and confirmed the Spanish-American War and World War I on military force for the country. In 1945, the United States had emerged from World War II to be the first country with nuclear weapons, a permanent member of the Security Council of the United Nations, and founding member of the North Atlantic Treaty Organization. As the United States became the only superpower in the world after the end of the Cold War and the disintegration of the Soviet Union. The amount the U.S. spends on the U.S. forces about 50 per cent of global military spending, is also an economic power, political and cultural world