See the only volcano on earth that can be explored from within

There is no denying that volcanoes are fascinating and attract, besides researchers, thousands of curious to contemplate their beauty. One of the most sought after countries for this type of tourism is Iceland, which has dozens of volcanoes - about 30 of them still active. And it is in the midst of this environment that you will find the only volcano in the world that can be explored from within.

The incredible experience takes place in the Thrihnukagigur (which can be translated into something like the "three peaks crater"), an exception among inactive volcanoes around the world. While solidified lava generally prevents access to the center of the volcano, here a huge crack allows its caves to be explored.

An opening of about 4x4 meters allows entry and gives access to a space of 150, 000 m³, located about 120 meters below the surface. The volcano was discovered in the 70's, but the first exploration took place in 1991 by Arni Stefánsson.

Interestingly, the explorer reports not having liked what he found there. "I came looking for beauty, but I only found ugly things." However, 17 years later, he returned to the site, taking a tour with better light equipment and more time to explore, a fact that completely changed his opinion of the space.

Image Source: Inside The Volcano

What draws the most attention inside the Thrihnukagigur is the variety of colors on its walls, a phenomenon that occurs thanks to the concentration of chemical elements present there, such as basalt, magnesium and iron.

No one knows exactly how all the lava in the volcano disappeared. For volcanologist Haraldur Sigurdsson, the Thrihnukagigur has its formation as a great mystery, but there are two possibilities: the lava may have solidified on its walls or returned to Earth. "It's as if someone had pulled the lid off a drain and all the magma had come down through it."

Image Source: Inside The Volcano

Although the Icelandic government encourages tourism inside the volcano and even plans to build tunnels to facilitate access to the interior, some courage is still needed to enter the Thrihnukagigur. Although it has been completely inactive for the past 4, 000 years, it gives no guarantee that it will never erupt again, as well as several other dangers such as tremors and earthquakes within.