Geyser
Yellowstone is the largest geyser locale, containing thousands of hot springs, and approximately 300 to 500 geysers. It is home to half of the world's total number of geysers in its nine geyser basins. It is located mostly in Wyoming, USA, with small portions in Montana and Idaho. Yellowstone includes the world's tallest active geyser (Steamboat Geyser in Norris Geyser Basin), as well as the renowned Old Faithful Geyser, Beehive Geyser, Giantess Geyser, Lion Geyser, Plume Geyser, Aurum Geyser, Castle Geyser, Sawmill Geyser, Grand Geyser, Oblong Geyser, Giant Geyser, Daisy Geyser, Grotto Geyser, the Fan & Mortar Geysers, & the Riverside Geyser, all in the Upper Geyser Basin which alone contains nearly 180 geysers.
Antofalla
Even later, several mafic centres grew southwest and west of the Antofalla complex. Fumarolic activity continues to this day, the existence of geysers was reported in 1962 and traces of an extinct geyser such as sinter structures have been found at Botijuelas. There are reports that the main volcano "smoked" occasionally such as in 1901 and 1911 and Antofalla is sometimes incorrectly considered the highest active volcano in the world, but the Global Volcanism Program considers the complex as Pleistocene in age, and no clear evidence of Holocene activity is found.