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Þríhnúkagígur
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Þríhnúkagígur is a unique natural phenomenon in the Blafjöll mountains near Reykjavík, famous for its fully preserved, empty magma chamber. Typically, such a chamber fills with lava after an eruption and solidifies, but here the molten rock mysteriously drained away, leaving the cavity accessible. The chamber has a massive volume of approximately 150,000 cubic meters and is deep enough to accommodate the Statue of Liberty. Since 2012, the volcano has been used for tourism, with visitors lowered 120 meters deep into the interior via an open elevator. The chamber walls glow in an incredible palette of colors, including reds, yellows, and purples, resulting from the various minerals in the rock. The name translates to 'Three Peaks Crater,' referring to the three distinct cones of the volcanic system. The last eruption occurred about 4,000 years ago, classifying the volcano as currently dormant. It is the only place in the world where you can safely descend into the heart of a volcano.
- Location: Iceland
- Top sights: Bláfjallafólkvangur · Þríhnúkar
- Nearby: Hafnarfjörður (14 km)
Best time to visit & climate
The most pleasant time to visit is Jun–Aug.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg °C | -1 | -1 | 0 | 3 | 6 | 9 | 11 | 10 | 8 | 4 | 1 | -1 |
| Rain mm | 179 | 162 | 161 | 123 | 96 | 86 | 105 | 121 | 184 | 149 | 149 | 182 |
📋 Practical info
Getting there
The dormant crater strictly requires a guided tour, starting with a three-kilometer hike across a rugged lava field, followed by a deep vertical descent in a specially designed open elevator.
Best season
Spectacular tours directly into the massive magma chamber generally operate exclusively during the warmer summer months when the approach hiking trails are safely and entirely accessible.
Terrain & paths
The demanding approach hike crosses rough and very uneven volcanic rock, while the vast interior of the massive cavern is extremely rocky and only dimly, yet artistically, artificially lit.
What to bring
Since the ambient temperature deep inside the volcano remains constantly cool near freezing, thick, warm clothing layers and very sturdy, ankle-high hiking boots are absolutely mandatory.
Parking
The designated starting point and the generous parking facilities are typically located exactly at the well-known Bláfjöll ski cabin, situated slightly off the beaten path on the capital region's outskirts.
Safety
Strict adherence to the safety instructions from experienced guides is crucial, and visitors must genuinely never, under any circumstances, leave the clearly marked safe zones deep inside the crater.
Time needed
For the complete, highly unforgettable experience, perfectly including the long approach hike, the slow vertical descent, and the fascinating time spent inside the cave, plan for a solid four to six hours.
Geography
Facts
- The magma chamber is 120 meters below the surface.
- The chamber's volume is approximately 150,000 cubic meters.
- The last eruption occurred about 4,000 years ago.
- The temperature in the chamber is constant at around 6 °C.
- The descent by elevator takes about 6 minutes.
- The cavity was discovered in 1974 by caver Árni B. Stefánsson.
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Notable places around
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Sights in the town Þríhnúkagígur (2)
Sights nearby
Frequently asked questions
What is unique about Þríhnúkagígur?
It is the only place in the world where you can descend into a volcano's magma chamber.
How do you get inside the volcano?
Visitors are lowered 120 meters down into the chamber via an open elevator system.
Is the volcano active?
No, it has been dormant for about 4,000 years and is considered perfectly safe.
Do you have to hike there?
Yes, a 45-minute hike (about 3 km) across lava fields is required to reach the base.
When are tours available?
Tours are typically available from May through October.
Þríhnúkagígur: where is it located?
Þríhnúkagígur is located in Iceland.
Þríhnúkagígur: what is there to see?
Highlights include Bláfjallafólkvangur, Þríhnúkar.
Þríhnúkagígur: when is the best time to visit?
The most pleasant time to visit is Jun, Aug.
Þríhnúkagígur: why is it worth visiting?
Þríhnúkagígur is a unique natural phenomenon in the Blafjöll mountains near Reykjavík, famous for its fully preserved, empty magma chamber.
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