Ol Doinyo Lengai

Ol Doinyo Lengai, Tanzania

The only known carbonatite volcano in the world (except for the neighboring Kerimasi volcano). The volcano produces natrocarbonatite lava with nearly unique minerals – nyerereite and gregoryite. Lava flows at very low temperature at 500 – 600 ° C. Carbonates react with the moisture of the atmosphere and quickly turn white, creating a unique volcanic landscape. Here in a steep cone has been observed formation of a new, nearly unique lava cave with enormous stalactites made of fragile natrocarbonatite.

Patomskiy Crater

Patomskiy Crater, Russia

Unusual crater – up to 40 m tall and 160 m wide mound/ring of limestone blocks with a smaller mound inside. Most likely it was created by a gaseous eruption some centuries ago.

Ikaite tufa columns in Ikka Fjord

Ikaite columns in Ikka Fjord, Greenland

Almost unique phenomenon – submarine tufa columns created by cold seeps from submarine springs. Columns are formed of ikaite – an unstable mineral that disintegrates in temperatures above 6 – 7 ° C. In total there are more than 600 such columns up to 18 m tall.

Oklo Mines – the only natural nuclear reactor

Flooded mine in Mounana, Oklo in Gabon

The only known site on Earth, where natural nuclear fission has taken place approximately 1.7 billion years ago in some 16 closely located sites. The evidence of this has been testified through an unusual composition of uranium, neodymium, ruthenium, and other materials.

Daikoku Sulfur Cauldron

Daikoku Sulphur Cauldron at the moment of discovery, Northern Marianas

A unique pool of liquid sulfur at the summit of a submarine volcano, one of the few in the world.

Usterling Growing Rock (Johannisfelsen)

Usterling Growing Rock, Bavaria

Almost unique natural landmark – a naturally formed tufa wall with a stream flowing along its upper rim and depositing further extension to this cliff. Wall is some 40 – 50 m long and up to 5.4 m tall.

Lake Bonney – lake in Antarctica with laughing gas

Lake Bonney from satellite, Antarctica. Inscription "Lake Bonney" is on the eastern lobe.

Frozen lake with unique geochemistry. The east lobe of the lake is saturated with nitrous oxide – "laughing gas" and dimethylsulfoxide. Another part of lake is rich with dimethylsulfide – possibly produced by microorganisms.

Naica Cave of the Crystals

In the Cave of the Crystals, Mexico

Cave with giant selenite crystals up to 12 meters long and 55 tons heavy. The air temperature in the cave is up to 58 °C high. Now flooded.