Augrabies Falls

Here the Orange River falls 56 meters into a deep gorge. During a flood, this becomes one of the most powerful falls in world.

Erta Ale

One of the most active volcanos in the world, with a constant lava lake (sometimes two lakes) in the crater, known since 1906. None of the other known lava lakes in the world have such a long lifetime.

Kalarskiy Geyser

Kalarskiy Geyser is a small geyser, or, rather intermittent thermal spring in remote, beautiful area of Siberia. Fountain is some 0.2 – 0.5 m high.

Benitoite Gem Mine (California State Gem Mine)

The only find of benitoite of gem quality.

Weeki Wachee Springs

Large spring, coming from a cave. The explored depth of cave is 124 m and thus it is the deepest freshwater filled cave in the United States. Explored length of passages – 7,260 m. Unique underwater theater – mermaid show – operates here since 1947.

Popa Falls (Popa Rapids)

Impressive rapids or waterfall across Okavango River. Falls are some 900 m wide and 2.5 – 4.5 m high.

Aouk-Kladuk Underground River

World’s most powerful underground river. Aouk-Kladuk Underground River is some 1.5 kilometres long. The stream has a volume of 130 – 180 cubic meters.

Keek sinkhole

One of the tiankengs of Aouk Underground River. Keek sinkhole is bell-shaped hollow that is some 160-180 m deep, its volume is 1.4 million cubic meters.

Hafasu Tiankeng

One of the tiankengs of Aouk Underground River. Hafasu Tiankeng is some 100 m deep, with a volume of 12 – 15 million cubic meters.

Kuom Tiankeng

One of the tiankengs of Aouk Underground River. Kuom Tiankeng is some 100 – 160 m deep, with a volume of 15 – 20 million cubic meters.