Yellowstone National Park in the context of Scatter plot

A national park is a nature park designated for conservation purposes because of unparalleled national natural, historic, or cultural significance. It is an area of natural, semi-natural, or developed land that is protected and owned by a government. Although governments hold different standards for national park designation, the conservation of 'wild nature' for posterity and as a symbol of national pride is a common motivation for the continued protection of all national parks around the world. National parks are almost always accessible to the public. Usually national parks are developed, owned and managed by national governments, though in some countries with federal or devolved forms of government, "national parks" may be the responsibility of subnational, regional, or local authorities.

The United States established Yellowstone National Park, the first "public park or pleasuring-ground for the benefit and enjoyment of the people," in 1872. Although Yellowstone was not officially termed a "national park" at the time, in practice it is widely held to be the first and oldest national park in the world. The Tobago Main Ridge Forest Reserve (in what is now Trinidad and Tobago; established in 1776) and the area surrounding Bogd Khan Uul Mountain (Mongolia, 1778), which were restricted from cultivation to protect surrounding farmland, are considered the oldest legally protected areas. Parks Canada, established on May 19, 1911, is the world's oldest national park service.

A hot spring, thermal spring, hydrothermal spring, or geothermal spring is a spring produced by the emergence of geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow bodies of magma (molten rock) or by circulation through faults to hot rock deep in the Earth's crust.

Hot spring water often contains large amounts of dissolved minerals. The chemistry of hot springs ranges from acid sulfate springs with a pH as low as 0.8, to alkaline chloride springs saturated with silica, to bicarbonate springs saturated with carbon dioxide and carbonate minerals. Some springs also contain abundant dissolved iron. The minerals brought to the surface in hot springs often feed communities of extremophiles, microorganisms adapted to extreme conditions, and it is possible that life on Earth had its origin in hot springs.

A geyser (/ˈɡaɪzər/, UK: /ˈɡiːzər/) is a spring with an intermittent water discharge ejected turbulently and accompanied by steam. The formation of geysers is fairly rare and is caused by particular hydrogeological conditions that exist only in a few places on Earth.

Generally, geyser field sites are located near active volcanic areas, and the geyser effect is due to the proximity of magma. Surface water works its way down to an average depth of around 2,000 metres (6,600 ft) where it contacts hot rocks. The pressurized water boils, and this causes the geyser effect of hot water and steam spraying out of the geyser's surface vent.

Genesee Park is a park in Jefferson County, Colorado. It is the largest park in the Denver Mountain Parks system, with a total of 2,413 acres (9.77 km). The land for Genesee Park was initially purchased in 1912 and the park area was largely complete by 1926.

The park contains two mountains, Genesee Mountain at 8,284 feet (2,525 m) above sea level and Bald Mountain at 7,988 feet (2,435 m) above sea level. The park also contains forests of ponderosa pine, Douglas-fir, and lodgepole pine. Interstate 70 traverses the park between exits 252 and 254 along the Lariat Loop Scenic & Historic Byway. On I-70 just west of exit 254, there are scenic overlooks for both directions for viewing the historic Bison herd, which live on maintained pastures on the north and south sides of I-70. The park's bison herd is owned by the City and County of Denver. Some of the original bison were acquired from Yellowstone National Park by the Denver Zoo and the City of Denver as early leaders in the conservation of bison. The bison herd moved here in 1914 and was expanded to Daniels Park in 1938. Thirty five bison were distributed to Native American tribes in 2023.

An extremophile (from Latin extremus 'extreme' and Ancient Greek φιλία (philía) 'love') is an organism that is able to live (or in some cases thrive) in extreme environments, i.e., environments with conditions approaching or stretching the limits of what known life can adapt to, such as extreme temperature, pressure, radiation, salinity, or pH level.

Since the definition of an extreme environment is relative to an arbitrarily defined standard, often an anthropocentric one, these organisms can be considered ecologically dominant in the evolutionary history of the planet. Extremophiles have continued to thrive in the most extreme conditions, making them one of the most abundant lifeforms. The study of extremophiles has expanded human knowledge of the limits of life, and informs speculation about extraterrestrial life. Extremophiles are also of interest because of their potential for bioremediation of environments made hazardous to humans due to pollution or contamination.

The Grand Prismatic Spring in Yellowstone National Park is the largest hot spring in the United States, and the third largest in the world, after Frying Pan Lake in New Zealand and Boiling Lake in Dominica. It is located in the Midway Geyser Basin.

Grand Prismatic Spring was noted by geologists working in the Hayden Geological Survey of 1871, and named by them for its striking coloration. Its colors match most of those seen in the rainbow dispersion of white light by an optical prism: red, orange, yellow, green, and blue.

Wyoming (/waɪˈoʊmɪŋ/ wye-OH-ming) is a landlocked state in the Mountain West subregion of the Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the southwest, and Colorado to the south. With an estimated population of 587,618 as of 2024, Wyoming is the least populous state despite being the tenth-largest by area, and it has the second-lowest population density after Alaska. The state capital and most populous city is Cheyenne, which had a population of 65,132 in 2020.

Wyoming's western half consists mostly of the ranges and rangelands of the Rocky Mountains; its eastern half consists of high-elevation prairie, and is referred to as the High Plains. Wyoming's climate is semi-arid in some parts and continental in others, making it drier and windier overall than other states, with greater temperature extremes. The federal government owns just under half of Wyoming's land, generally protecting it for public use. The state ranks sixth in the amount of land—and fifth in the proportion of its land—that is owned by the federal government. Its federal lands include two national parks (Grand Teton and Yellowstone), two national recreation areas, two national monuments, and several national forests, as well as historic sites, fish hatcheries, and wildlife refuges.

Travertine (/ˈtrævərtiːn/ TRAV-ər-teen) is a form of fresh water limestone deposited around mineral springs, especially hot springs. It often has a fibrous or concentric appearance and exists in white, tan, cream-colored, and rusty varieties. It is formed by a process of rapid precipitation of calcium carbonate, often at the mouth of a hot spring or in a limestone cave. In the latter, it can form stalactites, stalagmites, and other speleothems.

Travertine is frequently used in Italy and elsewhere as a building material. Similar, but softer and extremely porous deposits formed from ambient-temperature water are known as tufa.

Old Faithful is a cone geyser in Yellowstone National Park in Wyoming, United States. It was named in 1870 during the Washburn–Langford–Doane Expedition and was the first geyser in the park to be named. It is a highly predictable geothermal feature and has erupted every 44 minutes to two hours since 2000. The geyser and the nearby Old Faithful Inn are part of the Old Faithful Historic District.

Geobiology is a field of scientific research that explores the interactions between the physical Earth and the biosphere. It is a relatively young field, and its borders are fluid. There is considerable overlap with the fields of ecology, evolutionary biology, microbiology, paleontology, and particularly soil science and biogeochemistry. Geobiology applies the principles and methods of biology, geology, and soil science to the study of the ancient history of the co-evolution of life and Earth as well as the role of life in the modern world. Geobiologic studies tend to be focused on microorganisms, and on the role that life plays in altering the chemical and physical environment of the pedosphere, which exists at the intersection of the lithosphere, atmosphere, hydrosphere and/or cryosphere. It differs from biogeochemistry in that the focus is on processes and organisms over space and time rather than on global chemical cycles.

Geobiological research synthesizes the geologic record with modern biologic studies. It deals with process - how organisms affect the Earth and vice versa - as well as history - how the Earth and life have changed together. Much research is grounded in the search for fundamental understanding, but geobiology can also be applied, as in the case of microbes that clean up oil spills.

A pack is a social group of conspecific canines. The number of members in a pack and their social behavior varies from species to species. Social structure is very important in a pack. Canine packs are led by a breeding pair.

A complex volcano, also called a compound volcano or a volcanic complex, is a mixed landform consisting of related volcanic centers and their associated lava flows and pyroclastic rock. They may form due to changes in eruptive habit or in the location of the principal vent area on a particular volcano. Stratovolcanoes can also form a large caldera that gets filled in by a lava dome, or else multiple small cinder cones, lava domes and craters may develop on the caldera's rim.

Although a comparatively unusual type of volcano, they are widespread in the world and in geologic history. Metamorphosed ash flow tuffs are widespread in the Precambrian rocks of northern New Mexico, which indicates that caldera complexes have been important for much of Earth's history. Yellowstone National Park is on three partly covered caldera complexes. The Long Valley Caldera in eastern California is also a complex volcano; the San Juan Mountains in southwestern Colorado are formed on a group of Neogene-age caldera complexes, and most of the Mesozoic and Cenozoic rocks of Nevada, Idaho, and eastern California are also caldera complexes and their erupted ash flow tuffs. The Bennett Lake Caldera in British Columbia and the Yukon Territory is another example of a Cenozoic (Eocene) caldera complex.

Castle Geyser is a cone geyser in the Upper Geyser Basin of Yellowstone National Park. It is noted for the particularly large geyserite sinter deposits, which form its cone. These deposits have been likened in appearance to a castle.

When the geyser was given this name in 1870, the top edges of the structure resembled the typical profile associated with the modern concept of a castle, having the appearance of a large keep, multiple turrets, and especially because of the crenellation along the top edges of what resembled its towers. As the drawing below shows the cone had distinctive appearance at the time. Over time the cone's shape changes because of the layers of mineral deposited in successive eruptions.

The plains bison (Bison bison bison) is one of two subspecies/ecotypes of the American bison, the other being the wood bison (B. b. athabascae). A natural population of plains bison survives in Yellowstone National Park (the Yellowstone Park bison herd consisting of an estimated 4,800 bison). Multiple smaller reintroduced herds of bison in many ranges within the midwestern and western United States (including Alaska, but not Hawaii) as well as southern portions of the Canadian Prairies.

The conservation of bison in North America is an ongoing, diverse effort to bring American bison (Bison bison) back from the brink of extinction. Plains bison, a subspecies (Bison bison bison), are a keystone species in the North American Great Plains. Bison are a species of conservation concern in part because they suffered a severe population bottleneck at the end of the 19th century. The near extinction of the species during the 19th century unraveled fundamental ties between bison, grassland ecosystems, and indigenous peoples’ cultures and livelihoods. English speakers used the word buffalo for this animal when they arrived. Bison was used as the scientific term to distinguish them from the true buffalo. Buffalo is commonly used as it continues to hold cultural significance, particularly for Indigenous people.

Recovery began in the late 19th century with a handful of individuals independently saving the last surviving bison and the government efforts to protect the remnant herd in Yellowstone National Park. Dedicated restoration efforts in the 20th century bolstered bison numbers though they still exist in mostly small and isolated populations. Expansion of the understanding of bison ecology and management is ongoing. The contemporary widespread, collaborative effort includes attention to heritage genetics and minimal cattle introgression.

The United States has 63 national parks, which are congressionally designated protected areas operated by the National Park Service, an agency of the Department of the Interior. National parks are designated for their natural beauty, unique geological features, diverse ecosystems, and recreational opportunities, typically "because of some outstanding scenic feature or natural phenomena." While legislatively all units of the National Park System are considered equal with the same mission, national parks are generally larger and more of a destination, and hunting and extractive activities are prohibited. National monuments, on the other hand, are also frequently protected for their historical or archaeological significance. Eight national parks (including six in Alaska) are paired with a national preserve, areas with different levels of protection that are administered together but considered separate units and whose areas are not included in the figures below. The 433 units of the National Park System can be broadly referred to as national parks, but most have other formal designations.

A bill creating the first national park, Yellowstone, was signed into law by President Ulysses S. Grant in 1872, followed by Mackinac National Park in 1875 (decommissioned in 1895), and then Rock Creek Park (later merged into National Capital Parks), Sequoia and Yosemite in 1890. The Organic Act of 1916 created the National Park Service "to conserve the scenery and the natural and historic objects and wildlife therein, and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations." Many current national parks had been previously protected as national monuments by the president under the Antiquities Act or as other designations created by Congress before being redesignated by Congress; the newest national park is New River Gorge, previously a National River, and the most recent entirely new park is National Park of American Samoa. A few former national parks are no longer designated as such, or have been disbanded. Fourteen national parks are designated UNESCO World Heritage Sites (WHS), and 21 national parks are named UNESCO Biosphere Reserves (BR), with eight national parks in both programs.