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.
Gelai Volcano
Gelai Volcano stands at tall and is located in Tanzania in the Crater Highlands region. It is at the southeastern edge of Lake Natron in the East African Rift. Volcanic activity on Gelai dates to less than one million years ago. A number of earthquakes occurred in the area in the summer of 2007. Associated with the largest earthquake on 17 July a NNE-oriented fracture or narrow graben formed on the southern flank of Gelai. The fracture may be associated with the intrusion of a narrow dike at a depth of around .