Yellowstone National Park, Wyoming
This stream, leading from Grand Prismatic Spring in Yellowstone's Midway Geyser Basin, is totally lined with a microbial mat, giving it an reddish-orange color. This contrasts with the greenish-blue hue of the spring itself, which is lined with different species of microbes. The distant hills are softened by a combination of steam from the hot spring, low clouds, and falling snow.
Only standard changes to tone, contrast, and color were performed.
Nikon D800 with 24-70mm f/2.8 lens