Welcome to the caldera of the extinct Uzon volcano - one of the most unusual places in Russia. It is located in Kamchatka, in the Kronotsky Nature Reserve, and is included in the UNESCO World Heritage List as part of the Volcanoes of Kamchatka site.

Uzon is a giant depression, or caldera, which formed about 40,000 years ago after a powerful eruption and the collapse of an ancient volcano. Its dimensions are impressive: about 9 by 12 kilometers. Today, it is a huge basin with steep slopes and a relatively flat bottom at an altitude of about 700 meters above sea level. Nearby is the famous Valley of Geysers, just 20 kilometers away.

One of the attractions of Uzon is its incredible palette of colors. Yellow, orange, red, green, and even purple spots on the ground and in the water bodies are the result of active geothermal activity. The colors are created by minerals and chemical compounds: sulfur gives a bright yellow hue, iron produces a reddish‑brown shade, and various salts and silicon produce white and gray crusts. In the bodies of water themselves, the color is formed by thermophilic bacteria and algae that live in an extreme environment. Combined with clouds of steam and green vegetation, it looks like an alien landscape.

Here, more than a thousand hydrothermal manifestations are concentrated - from boiling mud pots to hot springs.

In the hot springs of Uzon, where the water temperature exceeds 90 °C and the concentration of toxic arsenic, mercury, and copper is lethal to all living things, unique bacteria and algae thrive. In 2008, a new geyser formed right in the caldera, which proves that Uzon remains geologically active even today.

Video and photos by Sergey Semenov, Stas Sedov, Sergey Shandin and Dmitry Moiseenko. Video editing by Ivan Dobromyslov

3 October 2026