For thousands of years, Native peoples moved in and out of the area that was to become Yellowstone National Park for ceremonies, hunting, and the medicines, minerals, and plants found there. Yellowstone was established as the first national park on March 1, 1872, and has remained an enduring inspiration for artists and scientists. Geology and botany specimens in the Smithsonian's collections from the 1870s Hayden expedition into Yellowstone still serve scientists studying changes in the Greater Yellowstone Ecosystem over time. When Hayden led the first geological survey of Yellowstone, he brought along a photographer, William Henry Jackson, and a painter, Thomas Moran, to document the area. Their images helped influence Congress to make Yellowstone the first National Park.