Part 2: This repeat installment takes the idea of national parks and wilderness conservation into the 20^th century. When I was a kid, I collected U.S. postage stamps, and there was a commemorative stamp devoted to conservationist John Muir – a five-cent stamp with a drawing of a man dwarfed by giant sequoia trees. After watching this episode, I learned why and how Muir earned his country’s stamp of approval. Check local listings.