It's scary enough to send your expensive drone and GoPro above an erupting volcano. But a group of daredevils from the U.S., Canada and New Zealand recently went a few steps further, sending themselves (and a GoPro) on a death-defying climb inside a very active volcano in Vanuatu.

Located on the mostly jungle-covered island of Ambrym, Marum is a deep volcanic crater with a large, roiling lava lake at the bottom. After reaching its 4,300-foot-high summit, American Sam Cossman and Canadian George Kourounis — guided by Geoff Mackley and Brad Ambrose of New Zealand — camped there for four days, twice rappelling 1,200 feet down into the ominous volcanic chasm.

Mackley has made several descents like this in recent years, often filming videos that show the storm chaser and adventurer in a protective suit near the edge of a churning lava pit. This time he and Ambrose served as guides for Cossman and Kourounis, who produced a short video about the August trip that has quickly gone viral — and deservedly so. The video above was uploaded by Cossman on Sept. 4 to Vimeo, where it has been viewed more than 1 million times in less than a week.

Kourounis, host of the adventure-reality TV series "Angry Planet," says the descent into Marum "was kind of like a reverse climbing of Everest," but with a few extra challenges such as extreme heat, splashing lava and acid rain. And despite some damage to a camera and his rain jacket, he tells The Huffington Post it was an "amazing expedition" and "the pinnacle adventure of my life."

In case that sentiment wasn't clear from his fist pumps in the video, Kourounis also made sure toformally express his enjoyment of the trip by taking a volcano selfie.

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Russell McLendon ( @russmclendon ) writes about humans and other wildlife.

This is what it's like to rappel into an active volcano
An epic new video follows four explorers into Vanuatu's Ambrym volcano, whose Marum crater holds a roiling lava lake.