The Native Americans or The indigenous peoples of the Americas are the pre-Columbian inhabitants of North and South America, their descendants, and many ethnic groups who identify with those peoples. They are often also referred to as Native Americans, Aboriginals, First Nations, and (by Christopher Columbus' geographic mistake) Indians, later disambiguated as Red Indians, American Indians, Amerindians, or Amerinds. According to the New World migration model, a migration of humans from Eurasia to the Americas took place via Beringia, a land bridge which connected the two continents across what is now the Bering Strait. The most recent point at which this migration could have taken place is c. 12,000 years ago, with the earliest period remaining a matter of some unresolved contention. These early Paleo-Indians soon spread throughout the Americas, diversifying into many hundreds of culturally distinct nations and tribes. According to the oral histories of many of the indigenous peoples of the Americas, they have been living there since their genesis, described by a wide range of traditional creation accounts. Application of the term "Indian" originated with Christopher Columbus, who thought that he had arrived in the East Indies, while seeking Asia. Later the name was still used as the Americas at the time were often called West Indies. This has served to imagine a kind of racial or cultural unity for the aboriginal peoples of the Americas. Once created, the unified "Indian" was codified in law, religion, and politics. The unitary idea of "Indians" was not originally shared by indigenous peoples, but many over the last two centuries have embraced the identity. While some indigenous peoples of the Americas were historically hunter-gatherers, many practiced aquaculture and agriculture. The impact of their agricultural endowment to the world is a testament to their time and work in reshaping, taming, and cultivating the flora indigenous to the Americas. Some societies depended heavily on agriculture while others practiced a mix of farming, hunting, and gathering. In some regions the indigenous peoples created monumental architecture, large-scale organized cities, chiefdoms, states, and empires. Many parts of the Americas are still populated by indigenous Americans; some countries have sizable populations, such as Bolivia, Peru, Paraguay, Mexico, Guatemala, Colombia, and Ecuador. At least a thousand different indigenous languages are spoken in the Americas. Some, such as Quechua languages, Aymara, Guaraní, Mayan languages, and Nahuatl, count their speakers in millions. Many also maintain aspects of indigenous cultural practices to varying degrees, including religion, social organization and subsistence practices. Some indigenous peoples still live in relative isolation from Western society, and a few are still counted as uncontacted peoples.