Yellowstone National Park is not a subtle place. It includes the caldera of one of the largest known volcanoes. It's a refuge for the largest and most impressive wild animals left in North America. It's big, colourful, and at times surreal.
In many cases, there is no sense of scale. The regions shown below could be nearly microscopic, or they could span many kilometres; there's no frame of reference. (These frames actually span a metre or two.)
The Grand Prismatic Spring at the Midway basin is among the most colourful natural features I've ever seen. The iridescent turquoise water is ringed by sulphurous yellow, which is itself surrounded by bright red and orange bacterial mats.
The pool of the Excelsior Geyser almost glows with vivid turquoise and blue hues. This particular geyser often lies nearly dormant for decades at a time before becoming violently active. Even when dormant, it churns out about 15,000 litres of boiling water per minute, and is constantly steaming.
Two completely different classes of life share a single stream here: the green plants we're all familiar with, and the unique, colourful sulphur-loving bacteria that are found in the geyser ponds.
And we can't forget Old Faithful, that iconic jet of water that draws tourists from all over the continent.