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 contradictory history of a dam that became a statement of American power and prestige.
Today one of the most-recognized figures in American literary history, poet Walt Whitman was denounced by critics in his own time.
Her 1963 warnings about the effects of pesticides and herbicides sparked a revolution in environmental policy.
In 1934, American polar explorer Richard Byrd became the first to experience winter in Antarctica's interior.
Robert Marshall, Aldo Leopold and Howard Zahniser dedicated their lives to protect the shrinking American wilderness.
In 1927, the Mississippi River flooded from New Orleans to Illinois, leaving a million people homeless and leading to a major black migration to the North.
This stunning film portrait of Yosemite National Park uses the 1851 diary of the first expedition of soldiers into the Native American territory.