Upper Geyser Basin, Yellowstone National Park, Wyoming, USA

© Ray Urner/Tandem Stills + Motio

Upper Geyser Basin, Yellowstone, USA

The world’s highest concentration of geysers and hydrothermal springs are found in this corner of Yellowstone National Park in the western United States. Here in Upper Geyser Basin, you’ll find perhaps the most famous of them all: Old Faithful, along with the tallest predictable geyser (Grand Geyser) and the most voluminous geyser (Giant Geyser). Yellowstone contains more than 10,000 hydrothermal features, including hot springs, mudpots, fumaroles (which release hot gases) and hundreds of geysers.