<P> The history of New Mexico is based on both archeological evidence, attesting to varying cultures of humans occupying the area of New Mexico since approximately 9200 BC, and written records . The earliest peoples had migrated from northern areas of North America after leaving Siberia via the Bering Land Bridge . Artifacts and architecture demonstrate ancient complex cultures in this region . </P> <P> The first written records of the region were made by the Spanish Conquistadors, who encountered Native American Pueblos when they explored the area in the 16th century . Since that time, the Spanish Empire, Mexico, and the United States (since 1848) have claimed control of the area . </P> <P> The area was governed as New Mexico Territory until 1912, when it was admitted as a state . The relatively isolated state had an economy dependent on mining . Its residents and government suffered from a reputation for corruption and extreme traditionalism . New Mexico introduced the atomic age in 1945, as the first nuclear weapons were developed by the federal government in the research center it established at Los Alamos . Ethnically the state has historically been divided among Native American, Hispanic and Anglo elements--the latter mostly migrants from Texas in the early years . </P> <P> Human occupation of New Mexico stretches back at least 11,000 years to the hunter - gatherer Clovis culture . They left evidence of their campsites and stone tools . After the invention of agriculture, the land was inhabited by the Ancient Pueblo Peoples, who built houses out of stone or adobe bricks . They experienced a Golden Age around AD 1000, but climate change led to migration and cultural evolution . From those people arose the historic Pueblo peoples who lived primarily along the few major rivers . The most important rivers are the Rio Grande, the Pecos, the Canadian, the San Juan, and the Gila . </P>

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