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.
Before radar had been invented a devastating hurricane hit America, surprising residents of the East Coast and killing more than 600 people.
Robert Marshall, Aldo Leopold and Howard Zahniser dedicated their lives to protect the shrinking American wilderness.
In 1934, American polar explorer Richard Byrd became the first to experience winter in Antarctica's interior.
This stunning film portrait of Yosemite National Park uses the 1851 diary of the first expedition of soldiers into the Native American territory.
When an earthen dam broke without warning, a small city in Pennsylvania was swept away in a wall of water over 30 feet high.
Vivid memories of those trapped in the terrifying temblor of 1906 that killed thousands of Californians.
High on a granite cliff in South Dakota's Black Hills tower the huge carved faces of four American presidents: George Washington, Thomas Jefferson, Abraham Lincoln, and Theodore Roosevelt.