Yellowstone National Park: Established in 1872, Yellowstone was America's first national park. Its creation marked an important milestone in the conservation movement.
Yosemite National Park: Yosemite became one of the earliest protected areas in the United States due to its stunning natural features and unique biodiversity.
Antiquities Act (1906): The Antiquities Act allowed presidents to protect federal lands as national monuments. This act facilitated the preservation of many significant sites that later became national parks.