Scientist observes erupting lava lake, Marum Volcano, Ambrym Island, Vanuatu

Climber tackles a cliff overhead erupting volcano crater, Marum Volcano, Ambrym Island, Vanuatu

Climbers erect a tent dangerously close to erupting lava, Marum Volcano, Ambrym Island, Vanuatu

Lava erupts vigorously behind volcanologist , Marum Volcano, Ambrym Island, Vanuatu

Climbers scale a cliff overhanging erupting lava lake, Marum Volcano, Ambrym Island, Vanuatu

Man stands on ridge as clouds of volcanic gas rise into air, Marum Volcano, Ambrym Island, Vanuatu

Climbers erect a tent dangerously close to erupting lava, Marum Volcano, Ambrym Island, Vanuatu

Gas blows past climber standing above lava lake, Marum Volcano, Ambrym Island, Vanuatu

Photographer documents erupting volcano up close, Marum Volcano, Ambrym Island, Vanuatu

Photographer and volcanologist study erupting volcano, Marum Volcano, Ambrym Island, Vanuatu

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A scientist with a headlamp walks inside a dark cave.

A volcanologist carries testing equipment to the edge of a smoking volcano.

A volcanologist stands on top of a volcano.

A volcanologist approaches a smoking volcano and crater.

A volcanologist stands atop a volcanic crater on the Kamchatka Penninsula, Russian Federation.

Smoke billows from a volcano where a volcanologist prepares testing equipment .

A volcanologist stands on a ridge overlooking a crater lake.

A volcanologist prepares testing equipment around the crater of a smoking volcano.

speleology explorer in a cave examining and securing a bolt on a rock 2

speleology explorer in a cave examining , looking around

Exploring

speleology explorer in a cave examining ancient rocks

speleology explorer in a cave preparing equipment