United States

The United States of America is a federal republic in North America made up of fifty states and a federal district. The geography and climate of the United States are extremely diverse, with deserts, plains, forests, and mountains that are also home to a wide variety of wildlife. It is one of the most multi-ethnic and multicultural nations in the world, the product of large-scale immigration from many countries.

The United States of America originated from the thirteen British colonies located along the Atlantic coast. The disputes between Great Britain and the colonies resulted in a conflict: on 4 July 1776 the delegates of the thirteen colonies drafted and unanimously approved the declaration of independence, which officially gave birth to a new federal state. The American Revolutionary War, which ended with the recognition of the independence of the United States from the Kingdom of Great Britain, was the first war for independence from a European colonial power. The Constitution was adopted on September 17, 1787, and has been amended twenty-seven times since then.

The United States undertook vigorous expansion throughout the 19th century, spurred by the controversial doctrine of Manifest Destiny. The acquisition of new territories and the admission of new member states also caused numerous wars with native peoples. The American Civil War ended with the abolition of slavery in the United States. The United States is a developed country, with an estimated 2021 gross domestic product (GDP) of $22.68 trillion.
The country represents a leading political force in the Western world, and is the leading economic and military power, also ranking first in the sector of scientific research and technological innovation.