The first to inhabit Baja California, Mexico, is believed to be over 11,000 years ago, traveling along the North American coast from Alaska. When Europeans arrived there were many tribes, some nomadic, some with a developed maritime economy. Throughout the 16th and 17th centuries, a wave of Spanish conquerors, discoverers, and missionaries found Baja California, until the Jesuits in 1697 were the first Europeans to settle. Another wave in the 18th century was marked by more settlement in and exploration of all of Baja California, Mexico. In 1804, Baja California was officially split north and south, which is still established to this day. Alta California was annexed by the US in 1848. Many different governing bodies and revolutions marked the 20th century. In 1952, Northern Territory of Baja California became the 29th state of Mexico, while, in 1972, Southern Territory of Baja California became the 31st. As of 2005 census, 2,844,469 are estimated to live in Baja California Norte (north), and 512, 170 in Baja California Sur (south).