Ken Burns must be running out of good ideas. The documentary filmmaker has famously done the Civil War, Lewis and Clark, baseball, jazz, Mark Twain, the Statue of Liberty, and the Brooklyn Bridge, among other subjects. What’s left?

The answer is, The National Parks: America’s Best Idea, running on most PBS stations nightly from September 27 to October 2. It might be Burns’s most ambitious effort yet, considering the outdoor cinematography from Acadia to Grand Canyon to Denali: a gorgeous tableau of cloud shadows drifting over red-walled canyons, rusty sunsets, waves crashing upon rocky shores, storms assailing craggy peaks, and cascading waterfalls. A feast for the eyes in high definition. Add the usual assortment of knowledgeable talking heads and Burns’s signature use of narration and still photographs, and you have a dazzling 12-hour infomercial for this “empire of grandeur.” But the history of the parks is one of personalities as much as landscapes, and it is riveting.

Yellowstone was America’s first national park, but Burns starts with Yosemite as a way to introduce the national parks’ patron saint: John Muir. Born in Scotland in 1838, Muir left the Wisconsin farm of his strict Calvinist youth to indulge a nature-absorbed wanderlust. He arrived in California in 1868, where he found employment building a sawmill for the first innkeeper to settle in Yosemite Valley. Here the “nature-struck pantheist” found his calling as an amateur naturalist, spending his free time indefatigably wandering in the Sierra Nevada. He slept in the open and could hike 25 miles a day while subsisting on a pocketful of crackers. And the “Thoreau of Yosemite” wrote about it all, however difficult that was. The man who closely studied 65 glaciers in the Sierra high country once wrote that “Writing is like the life of a glacier; one eternal grind.”

Muir helped found the Sierra Club in 1892, devoting much of his later life to writing in support of conservation. The Sierra Club famously fought—and lost—the Hetch Hetchy battle in 1918 (Muir had died in 1914), when the post-1906 earthquake water demands of San Francisco caused the Tuolumne River in that beautiful valley inside Yosemite National Park to be dammed. The fight marked the birth of the modern American conservation movement, singularly inspired by Muir’s life and work. Muir’s phrase describing his first glimpse of Yosemite is nicely illustrated by Burns: “The morning of creation” is the filmmaker’s main theme, a distinct departure from all his previous work. Unlike baseball or jazz, the national parks were invented only in administrative ways. In truth, they are timeless compliments to the American character. Yellowstone and Yosemite and others are the national landmarks of American exceptionalism, and the fact that we preserved them says a lot about us.

Meanwhile in Yellowstone, the 1871 Hayden Survey explored the mysterious region, previously the stuff of mountain man legend. It found and mapped a glorious landscape of mountains, rivers, and forests, amidst the world’s greatest concentration of “thermal features” (geysers, hot springs, steaming fissures, mudpots). Accompanying Ferdinand Hayden’s surveyors and scientists were two artists, the painter Thomas Moran and the photographer William H. Jackson. Their resulting work (including Moran’s famous painting “Grand Canyon of the Yellowstone,” now hanging at the Department of the Interior Museum) came to the attention of the public and the U.S. Congress, and legislation creating Yellowstone National Park was signed into law by President Ulysses Grant on March 1, 1872.

IN 1903, PRESIDENT THEODORE ROOSEVELT took a whistle-stop Western tour, visiting Yellowstone, Grand Canyon (“Leave it as it is; the ages have been at work on it, and man can only mar it,” went TR’s famous quote, as he stared into the canyon), and finally, Yosemite. Here with a small party the Executive Outdoorsman went camping with John Muir. Their late-night campfire chats resulted in national park status for Yosemite. Until then, Yosemite had been managed jointly by the federal government and the state of California.

TR the conservationist is best known for getting the Antiquities Act through Congress in 1906. Designed to preserve archaeological sites and artifacts at such places in the West as Mesa Verde and Chaco Canyon, the legislation paved the way for Roosevelt to create by executive order whole protoparks, his boldest stroke of the pen being the 806,000-acre Grand Canyon National Monument in 1908. Theodore Roosevelt is venerated by environmentalists today for adding by various methods 230 million acres to the federal public domain. During a speech at Yellowstone during his 1903 tour, TR dedicated the famous arch at the North Entrance that would bear his name and is inscribed with the words: “For the Benefit and Enjoyment of the People,” an inscription that sums up another primary theme of Burns’s documentary. It is that these national parks belong to every American, and we should strive to preserve and maintain them for our children and grandchildren as one component of the legacy of American democracy.

Early on, the parks—particularly Yellowstone— were managed by the U.S. Army. General Philip Sheridan, of Civil War and Indian Wars fame, and as military commander in the West, was Yellowstone’s first quasi-park superintendent. Troops were garrisoned at Fort Yellowstone (present Mammoth Hot Springs and modern Yellowstone’s Park Service headquarters), and spent most of their time pursuing and arresting bison poachers. But with the advent of the National Park Service (NPS) in 1916 (and even before that), two men made their marks as administrators: Stephen Mather and Horace Albright.

Mather was the first NPS director. He was independently wealthy (the Borax detergent fortune), and in the early years even used his own money to finance programs and pay underlings. Mather was the first to view the national parks as part of a system. As a young man he met John Muir, and later strove to maintain a delicate balance between the parks being promoted to the American public (railroad brochures, roads built to accommodate automobiles), and left in their pristine state as much as possible. During this time more parks joined the system: Glacier in Montana (1910), Mt. McKinley in Alaska Territory (1917), and in 1919, the trifecta of Acadia in Maine, Zion in Utah, and Grand Canyon in Arizona. In 1918 the parks passed the 1 million annual visitors mark. Mather died in 1930 and Albright—previously Mather’s secretary—succeeded him as NPS director, serving until the new Roosevelt administration in 1933. During this period (1916– 1933) the careers of Mather and Albright were the link between the pre-National Park Service of soldiers guarding the parks and arresting poachers Wild West fashion, and the modern NPS of informed and smartly uniformed rangers greeting tourists at Old Faithful or the south rim of the Grand Canyon.

Franklin Roosevelt visited national parks a number of times during his presidency, especially in the 1930s before he was distracted by World War II, and used the New Deal-era Civilian Conservation Corps (CCC) to build roads, trails, bridges, and cabins in the parks. Burns’s black-and-white newsreel footage shows the smiling president touring Glacier National Park and admiring the peaks from the back of his famous open-air touring car, and enjoying lunch with a fresh-faced CCC crew. Burns also features the stories of three surviving CCC members, as he presents the proposition that the parks—legends such as TR and John Muir notwithstanding—were really developed from the “bottom up.” FDR did such a good job of promoting the parks that visitation in 1939 passed 15 million. Not bad for Depression-era America. Great Smoky Mountains National Park in North Carolina was established on FDR’s watch in 1934.

THE PARKS IN THE POST-WORLD WAR II ERA exploded in popularity; for example, 1 million people visited Yellowstone in 1946, four times as many as 1945. War veterans and their baby boomer families took to the road each summer, inaugurating the tradition of the American family vacation. Budget cutbacks and rationing during the war years had left the infrastructure of the national parks in poor shape, but the country’s newfound prosperity meant that that would eventually improve. And President Eisenhower’s interstate highway system development through the 1950s made the parks more accessible to average citizens. The American love affair with the automobile and the national parks went hand in hand. Everglades National Park in Florida joined the roster in 1947, and Grand Teton National Park in Wyoming in 1950.

The 58 national parks and 333 national monuments and historical sites saw 275 million visitors in 2007. Technology has certainly found them. For instance, you can watch Old Faithful erupt on the Internet thanks to its webcam. A typical controversy today would be the battle over whether cell-phone towers should be erected in the middle of Yellowstone. The documentary concludes with the underlying admonition to be on our guard not to “love the parks to death.”

Ken Burns seems to have done it again, this time with a minimum of his standard politically correct posturing, whether on race (he does cover the “Buffalo Soldiers,” a black unit, guarding Yosemite in its early years, and Martin Luther King’s 1963 Lincoln Memorial speech with an NPS ranger at his side), or on environmentalism, offering a balanced view. If America itself is America’s best idea, then Burns has done a sweeping job of chronicling the second one.