All of the red-roofed, many-chimneyed buildings in the Mammoth area are part of historic Fort Yellowstone. Beginning in 1886, after 14 years of poor civilian management of the park, the Cavalry was called upon to manage the park's resources and visitors. Because the Cavalry only expected to be here a short while, they built a temporary post near the base of the Terraces called Camp Sheridan. After five cold, harsh winters, they realized that their stay in the park was going to be longer than expected, so they built Fort Yellowstone, a permanent post. In 1891, the first building to be constructed was the guard house because it directly coincided with the Cavalry's mission - protection and management. By 1916, the National Park Service was established, and the Cavalry gave control of Yellowstone back to the civilians. Since that time, historic Fort Yellowstone has been Yellowstone's headquarters.