Canyon National Park receives about five million visitors each year, a far cry from the annual visitation of 44,173 in 1919. Early history Current archaeological evidence suggests that humans inhabited the Grand Canyon area as far back as 4,000 years ago and at least were passers-through for 6,500 years before that. Radiocarbon dating of artifacts found in limestone caves in the inner canyon indicate ages of 3,000 to 4,000 years. In the 1950s split-twig animal figurines were found in the Redwall Limestone cliffs of the Inner Gorge that were dated in this range. These animal figurines are a few inches (7 to 8 cm) in height and made primarily from twigs of willow or cottonwood. This and other evidence suggests that these inner canyon dwellers were part of Desert Culture; a group of semi-nomadic hunter-gatherer Native American. The Ancestral Pueblo of the Basketmaker III Era (also called the Histatsinom, meaning "people who lived long ago") evolved from the Desert Culture sometime around 500 BCE. This group inhabited the rim and inner canyon and survived by hunting and gathering along with some limited agriculture. Noted for their basketmaking skills (hence their name), they lived in small communal bands inside caves and circular mud structures called pithouses. Further refinement of agriculture and technology led to a more sedentary and stable lifestyle for the Ancestral Pueblo starting around 500 CE. Contemporary with the flourishing of Ancestral Pueblo culture, another group, called the Cohonina lived west of the current site of Grand Canyon Village. Ancestral Pueblo in the Grand Canyon area started to use stone in addition to mud and poles to erect above-ground houses sometime around 800 CE. Thus the Pueblo period of Ancestral Pueblo culture was initiated. In summer, the Puebloans migrated from the hot inner canyon to the cooler high plateaus and reversed the journey for winter. Large granaries and multi-room pueblos survive from this period. There are around 2,000 known Ancestral Pueblo archaeological sites in park boundaries. The most accessible site is Tusayan Pueblo, which was constructed sometime and housed 30 or so people. Large numbers of dated archaeological sites indicate that the Ancestral Pueblo and the Cohonina flourished until about 1200 CE. But something happened a hundred years later that forced both of these cultures to move away. Several lines of evidence led to a theory that climate change caused a severe drought in the region from 1276 to