Þríhnúkagígur

Þríhnúkagígur is a dormant volcano near Kopavogur containing a massive magma chamber that extends roughly 213 meters (700 feet) into the rock below. The chamber walls display bands of mineral deposits in shades of orange, yellow, and red, showing the geological layers created during volcanic activity.

A cave explorer discovered this volcanic formation in 1974 and led investigations that revealed an unusual geological feature: an empty magma chamber without cooled lava inside. This finding showed that the volcano had experienced a complete and natural drainage of its magma reservoir.

The volcano holds special meaning for Icelanders as a place where music and geology merge. An Icelandic band recorded a song inside the magma chamber in 2015, showing how this space inspires contemporary artistic expression.

After a safety briefing, visitors take an elevator down into the chamber, making the descent comfortable without strenuous climbing. Meeting a guide at the parking area is part of the visit, and wearing warm layers is wise since temperatures drop noticeably deep underground.

This is the only place in the world where people can enter and explore an empty magma chamber, a phenomenon normally hidden beneath the earth's surface. The volcano's natural drainage created this rare opportunity to step inside a space typically sealed off from human access.