A stream runs through Yellowstone National Park. Yellowstone is America's first national park, established in 1872, and is located in Wyoming, Montana, and Idaho. President Barack Obama will visit Yellowstone National Park this weekend.
2 of 18
Geysers erupt in the Firehold Lake area of Yellowstone National Park.
3 of 18
Bison are one of the many animals that live in Yellowstone. The park is also home to grizzly bears, wolves, moose, and elk, among others.
4 of 18
Smoke drifts through trees burned during the LeHardy Fire in Yellowstone National Park. Last year was the 20th anniversary of the 1988 fires that swept through the park.
5 of 18
The Mammoth Hot Springs of Yellowstone National Park are seen, where heat, water, limestone, and rock fracture combine to create the terraces. Travertine is deposited as white rock, but organisms living there create the colors.
6 of 18
A moose wades in the river at Yellowstone.
7 of 18
The Opal terrace, part of the spring shown here, became active in 1926. The spring flows from the base of Capitol Hill in the park, and began depositing up to one foot of travertine per year, which created the terrace formation.
8 of 18
Snow falls on a stream in Yellowstone.
9 of 18
Yellowstone National Park has almost one-half of the world's hydrothermal features. There are over 10,000 of them in the park, with over 300 geysers. Here, a thermal spring is seen in the Norris Geyser Basin.
10 of 18
A fumarole cone is seen in Yellowstone lake. Fumaroles are holes or vents from which steam rushes into the air.
11 of 18
Sun rays combine with steam in the forest of one of Yellowstone's geothermal areas during the winter.
12 of 18
Bison stand in the road as an oncoming vehicle approaches in Yellowstone National Park.
13 of 18
The rapids and a waterfall of the Yellowstone River rush through the park.
14 of 18
The Yellowstone River is a tributary of the Missouri River and was used by Native Americans, early settlers, and early expeditions to the area that would later become Yellowstone National Park.
15 of 18
Allen Holder/Kansas City Star/MCT/NEWSCOM
Bacterial mats, shown here, are found near the hot springs and the geysers, and give the area the colorful landscape.
16 of 18
A forest and lake are covered with fog and mist in Yellowstone National Park.
17 of 18
Old Faithful was the first geyser in Yellowstone National Park to be named. It is a cone geyser named by the Washburn-Langford-Daone Expedition in 1870. Eruptions can shoot 3,700 to 8,400 gallons of boiling water as high as 185 for as long as 5 minutes. Eruptions often occur about 90 minutes apart. Old Faithful is smaller than the less predictable Steamboat Geyser, also found in Yellowstone.