Pretty, yes, but what about the people? Photo: National Park Service. North Americans love their heroes, and environmentalists are no exception. The hall of fame includes some of the biggest hitters from our nation's past: John Muir, David McTaggart, Marjory Stoneman Douglas, Paul Watson, David Brower, Rachel Carson, and Edward Abbey, to name just a few. Every Earth Day, speakers invoke these legends, yet there are also the lesser lights of the green pantheon: Alice Hamilton, the scientist who studied industrial lead poisoning and founded the modern discipline of occupational health; Crystal Eastman, the settlement-house worker who brought attention to …