Minerva Terrace, located within the Mammoth Hot Springs basin in northern portion of Yellowstone National Park. The step-like terraces form as the calcium carbonate dissolved in the heated water precipitate out as travertine. Minerva has gone through both active and inactive periods. In recent years, hot spring activity has shifted dramatically from Minerva to other features on the Lower Terraces, and back again. The colors are formed by various species of archaea bacteria and algae mats.