This guy quit his San Francisco tech job to create videos inside an active volcano

By any standard measure, Sam Cossman had a good gig.

He worked for Xola, a San Francisco company that helped provide services for outdoor guides and expedition providers, something connected to his own interest in exploration and adventure - he had spent time traveling and had built a company focused on adventure before that had been folded into Xola.

But in the summer of 2014 an opportunity unexpectedly presented itself that allowed him to travel to the island nation of Vanuatu in the South Pacific. There, he rappelled down into a volcano, bringing a GoPro camera and some other gear. And he captured some pretty incredible footage.

That video got a ton of interest online. People wanted to know more about the trip, more about the volcano - but they also wanted to know if he was going to go back to make more videos.

And thinking about it, his "sense of curiosity hadn't really been satisfied, it was such a quick trip," he tells Business Insider. So he decided to go back into the heart of the volcano, but it was going to take some time and planning to get everything together.

So he quit his job.

He gathered a crew, including a fellow climber and explorer, a drone pilot - flying drones inside a volcano spewing toxic gas is hard - and a writer and researcher gathering information on microbial life that exists in extreme environments, the sort of life that NASA might look for traces of while investigating volcanoes on other planetary bodies.

They made a plan to return to Vanuatu. They were going back to the lava lake at Marum Crater on Ambrym, the same spot Cossman had filmed before. And with the help of the team and with funding mostly from the photography accessory company Kenu, he made another video - an explorer's journey to the center of the Earth:

Pretty cool, right?

Business Insider spoke with Cossman to learn more about what it's like to walk around beside a lava lake in an active volcano - a spot so insane that locals call it the "entrance to hell."

BI: What's the first thing you notice when you are inside a volcano?

SC: It really feels like you're on another planet. You have goggles, a gas mask, a respirator... It's hot, 130 degrees, and it's over 1000 degrees in the lava, it's a sensory overload.

It's almost an out of body experience - you've not really seen or heard or felt or smelled anything like when you're down there. It sounds like a freight train because of the force of the energy coming out of that crater, a combination of a huge wave crashing and a river and a train, really loud. You can hardly hear yourself think.

BI: What do you see?

SC: The sights are also spectacular, it's blinding but like looking at a campfire. You really could only look at it for one or two seconds - cameras melt, your gas mask melts, even the gas masks that are designed to purify the air at that level of particulate matter, they can't quite.

The lava is very unpredictable, you might be half way down and see it crust over, but then it builds up pressure and explodes, turns into this raging explosive force, this dynamic thing... It's very unnerving, if you're focusing on a job at hand it's easy to get caught off guard by a huge splash of lava.

BI: What were the scariest moments?

SC: There were two - three.

First, I was walking next to the [lava] lake and my camera guy yells "hit the deck!" - and there was a massive splash of lava, and a very small piece hit one of us (luckily those protective suits are powerful). Lava is an interesting entity unto itself, it maintains the same level of density as a liquid or a solid, if you get a huge splash, not only will it burn you but it'll take you out.

Second, to climb up we used a motorized ascender, but one of the devices about halfway up we discovered had a fuel leak. I got stranded on the side of a vertical cliff, had to wait there with a climbing partner while another guy went up to get some fuel and spare parts, and around that time it started raining. What started like a harmless sprinkle turned into a raging torrent like a waterfall, and the water isn't like normal rainfall, it's acid rain, melting the skin off your hands, and with bowling ball sized rocks going by your head.

The other that I wish I would have captured on camera, I was on the descent down, and the footing is very loose, you swing depending on where the rope is (Cossman explained that they rappel down, carrying a large amount of gear, but sometimes have to swing to another spot to make their way down), and I caught myself and stabilized with my legs. That was enough to loosen a rock from 100 feet up, and it landed with a huge impact, knocked the wind out of me, on my collarbone. I thought I had broken my bone, but its fall was broken by my backpack strap - fortunately it didn't break any bones.

BI: What did you learn?

SC: I'd say one thing that this validated, that I'd begun to feel already, is that we as humans have so much capacity for greatness yet unless we really put ourselves into uncomfortable situations, you don't see what you're made of.

To look into a lava filled crater with so much force and perpetual energy and fire on Earth, it really gives you a glimpse into what you can imagine formed the Earth," he says. "It helps give you a perspective on things you rarely have the chance to see with your own eyes, it's a window in that ancient world, a visualization of creation.

BI: So what's next?

SC: I can't really talk about it yet, but suffice to say it will be equally exciting.

This interview and the questions asked were ordered and edited for length and clarity.