In 1934, American polar explorer Richard Byrd became the first to experience winter in Antarctica's interior.
Her 1963 warnings about the effects of pesticides and herbicides sparked a revolution in environmental policy.
The coal miners' battle for dignity led to the largest armed insurrection since the American Civil War.
The journey of Prince Maximilian, German naturalist, and artist Karl Bodmer, who explored the Mississippi River area from 1832-1834.
John Wesley Powell's epic journey into the unknown Grand Canyon was filled with adventure as his team mapped the Colorado River for the first time.
The most daring and innovative accomplishment at the turn of the 20th century.
This stunning film portrait of Yosemite National Park uses the 1851 diary of the first expedition of soldiers into the Native American territory.
Today one of the most-recognized figures in American literary history, poet Walt Whitman was denounced by critics in his own time.