This six-part documentary series directed by Ken Burns is the story of an idea as uniquely American as the Declaration of Independence and just as radical: that the most special places in the nation should be preserved, not for royalty or the rich, but for everyone.

While visiting the parks was once predominantly the domain of Americans wealthy enough to afford the high-priced train tours, the advent of the automobile allows more people than ever before to visit the parks. Mather embraces this opportunity and works to build more roads in the parks. Some park enthusiasts, such as Margaret and Edward Gehrke of Nebraska, begin “collecting” parks, making a point to visit as many as they can. In North Carolina, Horace Kephart, a reclusive writer, and George Masa, a Japanese immigrant, launch a campaign to protect the last strands of virgin forest in the Smoky Mountains by establishing it as a park. In Wyoming, John D. Rockefeller Jr. begins quietly buying up land in the Teton Mountain Range and valley in a secret plan to donate it to the government as a park.