The Scottish-born naturalist was one of the first nature preservationists in American history, inspiring others through his writing and his advocacy to keep the wilderness wild.

During his lifetime, the impact of his powerful voice could be seen in the preservation of the Yosemite and the sequoia groves of California, and the glacial landscapes of Alaska. His vision survived long after his death through the work of the Sierra Club, an organization he founded.

Shot in high definition in the spectacular landscapes that shaped Muir - and were, in turn, shaped by his devotion.

A diversity of images run through the program: the Wisconsin woods of his childhood, his incredible journey on foot through the American South, the Yosemite Valley, the California fruit ranch where he lived with his wife and daughters, the Alaskan wilderness that so attracted him, and the National Parks that he was so instrumental in creating.