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A topographical map of Idaho showing clearly the crescent-shaped depression of the Snake River Plain cutting through the the Idaho Rockies, shown in brown.

The Snake River Plain is a crescent shaped depression that extends across southern Idaho, taking up a quarter of the state's land area.

The Yellowstone hotspot currently underlies the Yellowstone Caldera. This diagram shows the volcanic activity happening around the hotspot, the same process that created the Snake River Plain.

The Snake River Plain is clearly visible in this satellite image as the pale, flat crescent cutting through the Rocky Mountains of Idaho.

The coloured circles represents the location of the Yellowstone hotspot as the North American plate moved over it from 15 million to 2,000 years ago, forming the Snake River Plain.

Buttes, such as this, pepper the flat surface of the Snake River Plain providing evidence of the volcanic activity that formed it.

Map showing the proposed locations of Earth's tectonic plates. The Snake River Plain was formed by the North American Plate moving south-westwards over the Yellowstone hotspot.

Volcanic features such as buttes are found along the Snake River Plain as reminders of how the plain was formed.

This diagram shows how a series of hotspot volcanoes such as those that formed the Snake River Plain is created. As the Earth's crust moves over the hotspot, a line of distinct volcanoes develop over time.

Location of Craters of the Moon National Monument in relation to the Snake River Plain and Idaho.

The Great Rift is a 100km long crack in the surface of the Earth, and was the point of origin for the volcanic activity that formed the Craters of the Moon.

Craters of the Moon Lava Field is the largest lava flow on the Snake River Plain. There are 60 separate lava flows that form the field.

Map showing Craters of the Moon National Monument, showing Craters of the Moon Lava Field and the smaller Kings Bowl and Wapi Lava Fields.

Star trails from within the belly of Great Owl Cavern. Craters of the Moon has several lava caves and tubes, formed by lava cooling after eruptions from the Great Rift.

Looking out over the Craters of the Moon National Monument Lava Field towards Blizzard Mountain.

Craters of the Moon Lava Field within the borders of the National Monument. The monument now covers an area half the size of Rhode Island, about 1,800km².

Big Cinder Butte stands out against the flat lava flow. With each eruption at Craters of the Moon, new lava covered over older volcanic formations.

The entrance to a lava tube in Craters of the Moon National Monument.

An example of the variety of unusual lava formations found in the Craters of the Moon National Monument.

Tourists inside a lava tube in the Craters of the Moon National Monument. Lava tubes are formed by the outside of a lava flow solidifying, while the warmer liquid lava inside flows out.

There are 25 volcanic cones preserved in Craters of the Moon National monument. Here, a path cuts through a cluster of cinder cones.

The desolate landscape of Craters of the Moon National Monument was created by eruptions that took place over 13,000 years.

Remnants of a burst lava bubble along one of Craters of the Moon lava flows.

Tunnels and caves are found across Craters of the Moon; this is Indian Tunnel Cave, a lava tube with a collapsed roof.

Craters of the Moon was designated as a national monument in 1924, and has since been extended in size to encompass the surrounding volcanic landscape.

Craters of the Moon Lava Flow spills out over the Snake River Plain from the Great Rift, which runs for 100km directly cutting across the plain.

1860 - Painting of a Shoshone village. Shoshone people were nomadic, migrating throughout the year to find food. Their travels took them through Craters of the Moon Lava Field.

The Craters of the Moon is one of the most inhospitable environments in the US with few plants or animals, little water and extreme weather conditions.

c. 1865 - A group of Shoshone men. The Shoshone were the most powerful tribe in the Rocky Mountains for thousands of years, and travelled across the Craters of the Moon.

The Shoshone people made their way across the Craters of the Moon each year in search of food on the lush plains beyond.

The Shoshone people travelled across this harsh landscape each year in search of food.

The Shoshone people would have crossed the lava flows at Craters of the Moon to make their way to hunting grounds east of the Snake River Plain.

1892 - Shoshone Indians on a reservation. While Shoshone culture has all but disappeared since Europeans arrived in America, their legend of the Craters of the Moon eruption has survived.

The Shoshone people lived and fished near Shoshone Falls, travelling east of the falls each year during their migrations, where they would cross Craters of the Moon.

Shoshone legend tells of a serpent that squeezed a mountain, causing it to erupt creating Craters of the Moon. This lava could be thought to resemble the snake's charred bones.

Looking across one of the Craters of the Moon lava flows towards the Lost River Mountains.

Lava beds cover most of Craters of the Moon National Monument. This is a harsh environment, where few species can survive.

c. 1895 - A Shoshone village. The Shoshones occupied the Snake River Plain and were known by other tribes as 'Snakes'.

Big Southern Butte is one of the largest volcanic domes in the world, and was created by eruptions that formed the Snake River Plain.