It is believed that a group of people belonging to the ancient MesoAmerican cultures (Mayan and Aztec) traveled north to settle in the area which is present-day southern Arizona. They came to this rugged valley formed by the slow running Gila and Salt rivers around 300 BC. They survived in this region by irrigating the land, and their advanced farming methods produced an ample supply of food to support their sizeable population. They lived there until 1500 AD and for reasons that are still a mystery, their culture began to fade, and subsequently vanished. The Pima called these remarkable people the "Hohokam" meaning the "vanished ones."