Throughout its history, the United States has been a nation of immigrants. In the early 17th century, settlers moved from Europe to the New World, established colonies, and replaced the native peoples who lived across the vast territories that would later become the United States. The settlers declared independence from Britain on July 4, 1776 and formed a Union of States based on a new Constitution. The nation continued to expand westward and although the country is a relatively young nation, it has rapidly become a global power.