Current understanding of the settlement of the Americas (human migration to and throughout the American continents) derives from advances in four interrelated disciplines: archaeology, Pleistocene geology, physical anthropology, and DNA analysis. While there is general agreement that the Americas were first settled from Asia, the pattern of migration, its timing, and the place(s) of origin in Asia of the peoples who migrated to the Americas remain unclear. In the 2000s, researchers sought to use familiar tools to validate or reject established theories, such as Clovis first. The archeological evidence suggests that the Paleo-Indians' first dispersal into the Americas occurred during the end of the last glacial period or, more specifically, what is known as the Last Glacial Maximum (LGM), around 16,500–13,000 years ago.