Old Faithful, Yellowstone National Park ranger naturalist service, NPS poster, ca. 1938
Ranger Naturalist Service: nature walks, field trips, camp fire - programs, nature talks. Yellowstone National Park U.S. Department of the Interior National Park Service. The poster (one of six showing different parks and monuments) from ca. 1938 shows Old Faithful geyser erupting.
[PD] This picture is in the public domain.