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.
Brothers Volcano
The Brothers Volcano is a Pacific Ocean submarine volcano in the Kermadec Arc, 340 kilometres north east of New Zealand's Whakaari/White Island. Within its oval outline, which measures 13 km by 8 km, it contains a 3 km wide caldera with walls 300-500 m high. It is three times bigger than the White Island. A dacite (dacite lava's viscosity is in between rhyolite and andesite) dome rises 350 m from the caldera floor (which lies 1850 m below sea level), with a smaller dome just to its northeast. The caldera walls and the larger dome host numerous hydrothermal vents, which send plumes of hot water 750 m up through the water column. It is the most hydrothermally active volcano known in the Kermadec Arc. These hydrothermal vents are also known as hot springs and have created an 8 meter high field of "black smoker" chimneys. These chimneys are created when the hydrothermal fluids hit the cold water and the chemicals in solution are deposited. The hydrothermal fluids are an energy source to many unique species of organisms like tubeworms and bacteria. The marine life and minerals found from these chimneys are beneficial to New Zealand's economy and biotechnology industry.