The volcano last erupted some 4,000 years ago, leaving an opening of approximately 4×4 meters in diameter, leading to a bottle-shaped volcanic vault. The magma chamber is about 120m deep and measures 50x70m at the bottom. An Icelandic tourist operator now provides curious adventurists a chance to explore this ancient volcano inside out.
A basket that holds 5–6 people and connected to a crane is lowered through the crater opening. The 120 meter descent takes about 7 to 8 minutes. Once inside, visitors can spend up to an hour in the magma chamber itself, during which they can see beautiful colourations on the rock surface and marvel at its enormous size. The ground space is equivalent to almost three full-sized basketball courts planted next to each other and the height is such that it would easily fit full sized Statue of Liberty into the chamber.
The tour is open only during the summers, given that the average temperature inside the volcano is always 6°C (43°F), which could make it rather difficult to visit in the winters. The next tour has been confirmed on 15th May, 2013.
The idea of making Thrihnukagigur volcano accessible came from Árni B. Stefánsson, a doctor in Reykjavik and a lifelong cave enthusiast. He has been studying caves in Iceland since 1954, and was the first to descend down the Thrihnukagigur, in 1974.
Árni insists that the preservation of caves and volcanic vaults is not about leaving them be. It´s rather about making sure that natural wonders like Thrihnukagigur are treated with care and respect – and made accessible in the right way. "Firstly this project is about preservation, then exploration, and finally education," Arni told The Guardian in an interview.. "It's not about volcanology, really. It's about the aesthetic … It's about beauty."
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