Old Faithful is a large, frequent, and regularly erupting geyser. A cone type of geyser, it is not the biggest, the most regular, or the prettiest geyser, but it has the best P.R. of nearly any natural feature in the world. It is indeed beautiful in the varied light of the Rocky Mountains. Under sunrise or sunset light it can turn gold. Under alpenglow it can be pink or magenta. Depending on the wind it can reveal a layered fountain of water fanning out as it flies 150 feet high, or the water can remain invisible inside a puffy, dense billowing cloud.