Geologist Rick Hutchinson watches over a spurt of activity from one of his charges – a steam hole in Yellowstone National Park, Wyoming, Aug. 4, 1978. Hutchinson is a “thermal ranger” for the park – he takes water samples, charts eruptions, monitors temperatures of the park’s estimated 10,000 thermal features. And he helps fish out coins, cans and other junk that visitors fling into the geysers. (AP Photo/John Kuglin)

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