A firefighter attempts to stop the fires near Norris Geyser Basin, August 20, 1988, better known as "Black Saturday" In Yellowstone National Park. More than 150,000 acres burned on that one day, and the smoke was so dense in places, it turned daytime into night. Image retrieved from NPS archives and taken by Jeff Henry...[1] of the Yellowstone Digital Slide Files which are all in the public domain [2]

该图片或媒体为美国国家公园管理局雇员在执行公务时创建。作为美国联邦政府的作品，此作品在美国境内属于公有领域。更多信息请参考美国国家公园管理局网站及美国国家公园管理局版权政策。