In 1971, a natural gas field collapsed in Turkmenistan, and to contain the spread of methane gas, geologists set it on fire. It has been burning continuously ever since.
This 5-foot-tall geyser in Nevada was accidentally created during well digging in 1964 to explore geothermal energy sources.
Once believed to be a meteorite impact structure, the Richat Structure in Mauritania is now thought to be an uplift exposed by erosion, though no conclusive studies exist.
A small cave at the base of this waterfall emits natural gas that can be lit to produce a small flame, which can burn for up to a year if not extinguished.
The world's largest salt flat formed when a prehistoric lake dried up. A thin film of water creates a mirror-like reflection on the salt surface.
This natural limestone cave in China is illuminated with multi-colored lighting, but the reason behind the colors remains a mystery.
This multi-hued, twisting slot canyon was formed by flowing water and subaerial processes in Utah.
Erosion of Navajo sandstone by flash flooding and subaerial processes created this beautiful slot canyon in Arizona.
Known for its natural acoustics, this cave was formed by contraction and fracturing due to differential heating and cooling on solidified lava surfaces.
Colored mountains in China were created by natural weathering and erosion of red sandstone and conglomerate laid down by sedimentation from lakes and streams.
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