Timeline: from creation to conservation

1805

The Lewis and Clark expedition encounters Nez Perce, Crow and Shoshone tribes when travelling through Montana

1871

Ferdinand Hayden creates a geological survey with paintings by Thomas Moran and photography by William Henry Jackson

1872

President Ulysses S Grant signs the Yellowstone National Park Protection Act ‘for the benefit and enjoyment of the people’

1978

Yellowstone is named a UNESCO World Heritage Site, along with Mesa Verde National Park in Colorado

1995

Wolves are reintroduced from Canada, and in 2008 Northern Rocky Mountain wolves are removed from the endangered species list