Perhaps the single most iconic geyser of Yellowstone (and perhaps the world) is Old Faithful, so called for its predictable eruption behavior. Actually, it's not that predictable, but it erupts often enough to just visit any time and wait until the next eruption. Hence a veritable cottage industry has arisen around it, and one almost gets the impression seeing a geyser eruption in a baseball stadium. However, along the Firehole River - into which Old Faithful empties its eruption water - there are many moregeothermic phenomena, and walking the Artemisia trail along the river is walking in a kind of fairytale landscape. Luckily, the Artemisia trail is far lesscrowded and yet full of geothermic wonders - an unforgettable experience on our last day in Yellowstone.