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.
Long Island (Papua New Guinea)
Two stratovolcanoes are located on the island: Mount Reaumur and Cerisy Peak. The summit of the volcanic complex collapsed during at least three major explosive eruptions, about 16,000, 4000, and 300 years ago. These produced a large caldera 10 x 12.5 km in size, now filled with a freshwater crater lake, Lake Wisdom. In 1953-1954 and 1968, volcanic activity created Motmot Island on the crater lake, 200 x 200 m in size. The 1660 eruption was one of the largest in Papua New Guinea's recent history with an estimated air-fall volume in excess of 11 cu km, comparable to the 1991 eruption of Mount Pinatubo, but the Global Volcanism Program gives a much higher estimate of 30 cu km. This cataclysmic event prompted legends of a "Time of Darkness". The most recent (and a smaller) eruption occurred in 1993.