How to trek to two of the world’s largest known caves

It’s a four-day hike through leech-filled jungle to reach Vietnam’s Hang En and Hang Son Doong caves.

This story appears in the June 2019 issue of National Geographic magazine.

Italian physicist and photographer Alessandro Cerè took a break from work at the Centre for Quantum Technologies in Singapore to venture into Hang En and Hang Son Doong, two of the top three largest known caves in the world. To get there, a punishing path and 90 percent humidity test even the fittest hiker.

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A walk for the fortunate few: Only a limited number of travelers are allowed to visit these caves each year, but Cerè snagged a last-minute spot through a friend of a friend. Looking at photos online, he knew he’d need a lens that could handle the light contrasts inside the caves and decided to invest in new camera equipment. As the trip approached, Cerè ran every day to prepare for the physical toll of hiking and climbing in the sweltering jungle.


Essential packing list: The trip poses at least one confounding packing problem: It’s wet and muddy, but nonbreathable waterproof boots can breed foot infections.

  • Permeable hiking shoes that dry quickly
  • Foot powder to prevent bacterial infection
  • A waterproof bag to store essentials during river crossings
  • Long pants and long-sleeve shirts to protect from leeches
  • Tablets to replace electrolytes lost in sweat
  • A tripod to stabilize the camera in low light


Ready for launch: The expedition members met in Hanoi for a few days to get to know each other and then took a quick flight to Dong Hoi. Entering the jungle, Cerè switched his phone off, glad to be unreachable. The narrow paths flowed up and down. The group spent four days wading through hip-high waters before traversing through and camping in soaring caves. At the end of Hang Son Doong stood the Great Wall of Vietnam, a 200-foot barrier to be conquered by both ladder and rope climbing.


Miles hiked over four days

Feet high inside Hang En

Pounds of photo gear in pack