Monument Geiser Basin. Yellowstone has the largest concentration of geisers in the world. The early explorers were in awe of everything they came across in the park. It took almost 75 years, after the first explorer came through, for the government to believe that it all really exsisted. Yellowstone was made the first national park soon after the Washburn expedition in 1872. They believed the area was too beautiful and strange for any one person to have ownership. The whole country should share in it.