Yellowstone National Park, now 145 years old, was the first national park established in the world. In 2016, the 2.2-million-acre park was visited by a record 4.2 million people who came to experience the wilderness, explore countless geothermal features, witness the gorgeous vistas, and try to catch a glimpse of the resident wildlife. Gathered here are a handful of compelling photos from Yellowstone’s past, as well as some from recent years.