Palette Spring is one of the more active features at Mammoth Hot Springs. Carbonate-laden water percolates up from the top of the hill and then cascades down in rivulets, forming this large structure (note the small evergreens on the left -- this view encompasses a good 30 or more feet across.)

The orange color is created by thermophilic bacteria that thrive in the hot water run-off from the spring. These are found near many of Yellowstone's springs, as we'll discover later in this SceneSet.