All Photos © Carsten Peter/National Geographic. Above: The lava at Nyiragongo is made of an alkali-rich volcanic rock; its unusual composition may be a factor in the lava’s fluidity.

Photographer Carsten Peter descended into the fiery center of Nyiragongo—an active volcano towering over a city of one million people in the Democratic Republic of the Congo—for the April issue of National Geographic magazine.  See Carsten and his team explore the depths of Nyiragongo in Man vs. Volcano on the National Geographic channel. To see more of Carsten Peter’s work click here.

A member of the expedition walks on the caldera’s cooled lava floor, turned red by the reflected glow of the lake. “Down here you feel the volcano,” says photographer Carsten Peter. “It’s a low-frequency rumbling that pulses through your body – like being inside a giant subwoofer.”

Traders ferry logs and charcoal 12 miles from the forests around Nyiragongo to Goma, which continues to swell with refugees fleeing the Democratic Republic of the Congo’s war-torn east. The plume rising from the mountain reminds residents of yet another threat: eruption.

Many of the porters were local women, who huddled in the cold at the crater rim.

Rising gas bubbles explode, splattering lava up to 60 feet in the air over Nyiragongo’s fiery lake.

Constant bubbling sends waves of lava lapping over the rim. Scientists aren’t sure of the lake’s depth, though recent lava samples indicate the magma originated in the Earth’s mantle more than 46 miles below.

Photographer Carsten Peter tests the thermal suit that Sims used to get close to the lava lake. “It can protect you from the radiant heat, but if you get hit with a lava splatter, the force will likely kill you,” he says. For 30 years Peter has explored volcanoes around the world. “Seeing at close range the primal forces that shaped the planet can be hypnotic. You cannot allow yourself to fall under a volcano’s spell, especially one as unpredictable as Nyiragongo. That can be a fatal mistake.”