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.

T MINUS ONE MONTH

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.

T MINUS ONE WEEK

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

T MINUS ZERO DAYS

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.

BY THE NUMBERS

28
Miles hiked over four days

459
Feet high inside Hang En

55
Pounds of photo gear in pack

<p>A cave explorer stands atop a large spiral stalagmite in the Watch Out for Dinosaurs area, a sinkhole inside Son Doong. Part of the cave ceiling collapsed, letting sunlight into the cave and allowing for grass and plants to grow.</p>

A cave explorer stands atop a large spiral stalagmite in the Watch Out for Dinosaurs area, a sinkhole inside Son Doong. Part of the cave ceiling collapsed, letting sunlight into the cave and allowing for grass and plants to grow.

Photograph by Martin Edström, Nat Geo Image Collection

More from this series

A Look Inside One of Earth’s Most Dramatic Volcanoes
How to Tightrope Across the Alps
See the millennia-old formations underneath Yellowstone

Go Further

Subscriber Exclusive Content

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet