North America is the third-largest continent, covering about 24.7 million square kilometers (16.5% of Earth's land area) and home to over 592 million people as of 2021, making it the fourth-most populous. It spans the Northern and Western hemispheres, bordered by the Arctic, Atlantic, and Pacific Oceans, and is typically divided into Northern America (Canada, Greenland, the United States) and Middle America (Mexico, Central America, and the Caribbean). Humans have lived there for at least 20,000 years, with the Paleo-Indian period lasting until about 10,000 years ago, followed by Archaic and Classic stages, while Norse exploration began in the late 10th century with settlements in Greenland and Newfoundland. From 1492, Christopher Columbus's voyages triggered a major transatlantic exchange and European colonization, which shaped modern cultural and ethnic patterns, leading to the prevalence of English, Spanish, and French alongside Western traditions, though many indigenous cultures persist. The continent is named after Amerigo Vespucci, with cartographers Martin Waldseemüller and Matthias Ringmann first using "America" in 1507, and Gerardus Mercator later applying it to North America. Today, its 23 independent states and territories reflect a rich blend of European settlers, indigenous peoples, enslaved Africans, and later immigrants from Europe and Asia, creating a highly diverse cultural landscape.