Tucked away in the Khammouane province of Laos is a tourist attraction called the Tham Khoun Xe, or Khoun Xe cave. The 4-mile-long river cave is one of the largest in the world, featuring passage walls that are an average of 249 feet wide and 184 feet tall. While its massive and beautiful tunnels are open to the public, the site's remote geographic location makes it hard for most people to access. But you can still get to a small glimpse of the cave, thanks to drone footage from Beijing-based photographer Ryan Deboodt.

In an interview with Smithsonian.com, Deboodt spoke about the experience of kayaking into the cave for two days and flying his DJI Phantom Three drone through the darkness. Tourists are typically allowed to go around 300 meters (984 feet) into Khoun Xe, but the photographer and his crew got to see it all, by invitation from the national park that oversees the site.

"It’s very empty, but then you look up in the distance and see these huge stalagmites," Deboodt said. "It’s a very strange feeling—it’s so empty and yet there’s so much big stuff on the sides."

Still, capturing the experience wasn't easy. While some people might assume that caves like Khoun Xe are pre-lit, the video shows that's not the case at all. In fact, the only light sources are from the outside (like, Deboodt's flashlights) and glowing lights on the kayaks.

Deboodt chose to shoot the video with a drone instead of relying solely on still photography because it "just creates a new perspective for me on the caves and a new challenge," he said. "Cave photography is already really difficult, and filming is another step up. You have to deal with all the movements, and it’s quite a bit harder. I like the challenge involved with it."

But not all of the Deboodt's sightings made it into the footage. For instance, the team witnessed evidence that massive spiders made their home in the cave. "In some parts of cave, you can find their legs," he said. "We saw these things that looked kind of like sticks, but it turned out they were big spider legs … It’s not something that you really care to run into in the dark."

Check out the video above for more on the hidden treasure.

Images via Vimeo

[h/t Smithsonian]