A Window Into Hell: Places Where Gases Melt Gear, and People Still Go Back

A few months earlier, on his first trip back to that same spot, toxic gases had literally melted his face shield and respirator. He went back anyway.

This isn't a scene from a science-fiction film. It's a modern form of adventuring practised by a handful of people on the planet -professional explorers, scientists, and, increasingly, tourists willing to pay for a ticket to what looks like the entrance to hell.

A Window Into Hell in the South Pacific

In 2015, Cossman and Canadian explorer George Kourounis descended twice into the Marum crater, on Ambrym Island in the Vanuatu archipelago - one of only seven places on Earth with a permanent, standing lake of molten lava. The descent ran roughly three hundred and sixty-five metres - Kourounis compared it to "a reverse climb of Everest" - down a nearly vertical, unstable rock face, through temperatures that topped a thousand degrees Celsius, rain so acidic it could, in his words, have come straight out of a car battery, and gas that was corroding their equipment in real time.

"The volcano fought back at us," Kourounis described the experience. "We had to deal with terrible weather, tremendous heat from the lava, ascending and descending four hundred metres of near-vertical, loose rock, acid rain so strong it could have come from a car battery, and a variety of other craziness." A decade earlier, that same Kourounis had been lowered roughly sixty metres into the crater of Erta Ale, in Ethiopia's Danakil Desert, where he spent half an hour filming while standing on a freshly hardened crust above a lake of lava, in a protective thermal suit.

The World's Largest Lava Lake, Without a Single Railing

While Marum remains the more technically demanding undertaking, Mount Nyiragongo in the Democratic Republic of Congo offers something rarer: the chance, with guides and the right permit, to hike to the crater's edge on your own two feet, without specialized climbing gear. Nyiragongo's crater holds the largest lava lake on the planet - so large, according to the scientists who study it, that every other lava lake in the world could fit inside it with room to spare.

The climb takes about five hours over five kilometres, and guides describe the terrain as a "drone graveyard" - nearly every attempt to film the volcano from the air ends with the device crashing from the heat and turbulence. At the very top, there are no barriers or railings between visitors and the crater, and just over a decade ago one visitor died after falling in. And yet it's precisely that combination of accessibility and danger that seems to make Nyiragongo one of the most sought-after volcanic experiences in the world for serious adventurers.

Two People Who Loved Volcanoes More Than Their Own Lives

No story about the fascination with volcanoes can skip Katia and Maurice Krafft, the French volcanologist couple whose shared life, and shared death, became the subject of the 2022 documentary Fire of Love. They met at the University of Strasbourg, married in 1970, and spent the next twenty years travelling from one eruption to the next - she a physicist and chemist, he a geologist - documenting volcanoes on film and in photographs in a way that had never been done before.

Maurice once said that when he died, he wanted it to be "on the edge of a volcano." Katia added that if he died first, she'd want to be right behind him at that very moment. They both got exactly what they'd wished for: on 3 June 1991, while observing an eruption on Mount Unzen in Japan, a pyroclastic flow - a cloud of superheated gas and ash moving at highway speed - killed them both, along with American volcanologist Harry Glicken and roughly forty firefighters and journalists who happened to be nearby.

The Gear That Separates Adventure From Suicide

What separates serious explorers from catastrophe isn't courage, but equipment and knowledge of the terrain. Protective thermal suits for approaching lava are made from an aluminised fibreglass shell with an inner lining of fire-resistant Nomex, capable of withstanding brief exposure to temperatures over a thousand degrees. The suit is paired with respirators fitted with filters for sulphurous gases, a gold-plated visor that reflects heat radiation, and climbing gear sturdy enough to handle a descent down hundreds of metres of unstable volcanic rock.

Even with all that equipment, the margin for error stays thin. Toxic gases can melt gear within minutes, as happened to Cossman; the heat can cause instant burns if the protective suit is breached even briefly; and the terrain itself, made of unstable, freshly hardened rock, doesn't forgive carelessness the way an ordinary, non-volcanic mountain does.