Yellowstone National Park is a protected area showcasing significant geological phenomena and processes. It is also a unique manifestation of geothermal forces, natural beauty, and wild ecosystems where rare and endangered species thrive. As the site of one of the few remaining intact large ecosystems in the northern temperate zone of earth, Yellowstone’s ecological communities provide unparalleled opportunities for conservation, study, and enjoyment of large-scale wildland ecosystem processes.br br The extraordinary scenic treasures of Yellowstone include the world’s largest collection of geysers, the Grand Canyon of the Yellowstone River, numerous waterfalls, and great herds of wildlife.br br Yellowstone is one of the world's foremost sites for the study and appreciation of the evolutionary history of the earth. The park has a globally unparalleled assemblage of surficial geothermal activity, thousands of hot springs, mudpots and fumaroles, and more than half of the world’s active geysers. Nearly 150 species of fossil plants, ranging from small ferns and rushes up to large Sequoia and many other tree species, have been identified in the park’s abundant fossil deposits. The world’s largest recognized caldera (45 km by 75 km – 27 miles by 45 miles) is contained within the park.