USA/WY: Yellowstone NP – Norris Geyser Basin
Yellowstone National Park is all about the geothermal features and of all the geyser basins, Norris Geyser Basin is the largest and the oldest and the hottest (although not the most spectacular). Almost all of the many geysers and pools in Norris are near the boiling point as the basin is the most proximate to the massive underground hotspot. The Norris Basin has existed for around 115,000 years, constantly changing and evolving with new fields and geysers erupting every year. The vast majority of the waters at Norris are acidic, including acid geysers which are very rare. There are dozens of geysers at Norris Basin, from small to super giant. Steamboat Geyser, located in Norris, is the tallest geyser in the world at 300–400 feet (91–122 m), although it is not a regularly erupting geyser.