Americas

The Americas (or America) are lands in the Western Hemisphere that are also known as the New World. Comprising the continents of North America and South America, along with their associated islands, they cover 8.3% of the Earth's total surface area (28.4% of its land area). The topography is dominated by the American Cordillera, a long chain of mountains that run the length of the west coast. The flatter eastern side of the Americas is dominated by large river basins, such as the Amazon, Mississippi, and La Plata. Extending 14,000 km (8,699 mi) in a north-south orientation, the climate and ecology varies strongly across the Americas, from arctic tundra of Canada, Greenland, and Alaska, to the tropical rain forests in Central America and South America. When the continents joined 3 million years ago, the Great American Interchange resulted in many species being spread across the Americas, such as the cougar, porcupine, and hummingbirds.

Humans first settled the Americas from Asia between 40,000 BCE and 15,000 BCE. A second migration of Na-Dene speakers followed later from Asia. The subsequent migration of the Inuit into the neoarctic around 3500 BCE completed what is generally regarded as the settlement by the Indigenous peoples of the Americas. The voyages of Christopher Columbus from 1492 to 1502 resulted in permanent contact with European (and subsequently, other Old World) powers, which lead to the Columbian exchange. Diseases introduced from Europe and Africa devastated the Indigenous peoples, and the European powers colonised the Americas. Mass emigration from Europe, including large numbers of indentured servants, and forced immigration of African slaves largely replaced the Indigenous Peoples. Beginning with the American Revolution in 1776 and Haitian Revolution in 1791, the European powers began to decolonise the Americas. Currently, almost all of the population of the Americas resides in independent countries; however, the legacy of the colonisation and settlement by Europeans is that the Americas share many common cultural traits, most notably the predominant adherence to Christianity and use of Indo-European languages; primarily Spanish, English, and Portuguese. More than 900 million people live in the Americas (about 13.5% of the human population), the most populous countries being the United States, Brazil, and Mexico, the most populous cities being Mexico City, São Paulo, and New York City.