Volcanoes fume beneath Iceland’s Vatnajökull glacier, a sprawling ice field about the size of Rhode Island and Delaware combined.

In October 1996 a new fissure—Gjalp—erupted, burned through the glacier, spewed ash high into the sky, and unleashed a catastrophic meltwater flood.

Rope up with online correspondent Ford Cochran and follow world-renowned volcanologist Haraldur Sigurdsson as he climbs, crawls, and paddles his way deep into the belly of this smoldering beast.

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