Grand Teton

Declared in 1929 and considerably extended in 1950 thanks to land bought and given by John D. Rockefeller Jr. — who quietly acquired thousands of hectares of the Jackson Hole valley over years, to keep prices from soaring, before handing them to the federal government — it protects one of the geologically youngest ranges in the Rockies, thrown up barely 10 million years ago by a fault that lifts it abruptly from the valley floor with no foothills before it, which makes it unmistakable on the horizon.