It was the nation's best idea, Ken Burns, says: the national parks system.

It was the nation's best idea, Ken Burns, says: the national parks system.

Americans can appreciate the 58 parks for their majesty and for the once-revolutionary concept of setting aside the country's most precious natural resources for all citizens to use, he says. Their histories unfold in the documentarian's latest series, starting tonight on PBS.

Many people who visit a park have a very personal connection — just like Burns.

Burns, partner Dayton Duncan and their company worked for 10 years on the 12-hour series. Toward the end, Burns spent five days working in the Yosemite national park.

He looked forward to rest when it was over, but couldn't sleep: Burns' memory drifted back to 1959, when he was 6 and his father took him to Shenandoah National Park in Virginia. His mother was dying of cancer at the time.

"I could remember what his hand felt like when he took me for a walk in the park," he recalls. "I could remember the songs he sang. I was given back that experience. When this amazing moment happened it was deeply spiritual."

He credits Yosemite for the experience.

Big ideas and small adventures were involved in creating the parks. That's perfect for Burns' style, which transports willing viewers into another time and place. He explores the lives of John Muir and Stephen Mather, leaders of land conservation a century ago. But in working with a Nebraska historian on another project, he learned of the lives of Margaret and Edward Gehrke, an ordinary couple that tried to see as many parks as possible, and left behind lovingly curated photo albums of their trips.

"This film is not a travelogue," Burns says. "It is not a nature film. It is a history; it is full of drama and conflict."