Opalescent pool in the Black Sand Basin, Yellowstone National Park, UNESCO World Heritage Site, Wyoming, United States of America, North America

travel destination travel destinations travel photography colour colour image color color image horizontal horizontal image outdoors outside day nobody no one no one opalescent pool black sand basin yellowstone national park unesco unesco world heritage site world heritage site wyoming usa us united states united states of america north america american north american non urban scene geology geological pool water mineral geothermal tree trunk dead decay bare hill forest