An exploratory trip into the ‘underground heaven’ of Son Doong – the world’s largest cave – is an unforgettable experience.

The 50km round trip includes crossing 40 large and small streams, climbing up and down 20km worth of steep slopes, and most memorably a 500m one right at the end of the journey.

A group of ten friends, nine from the U.S., joined a team of more than ten porters, two forest rangers, two cooks, one tour guide and two British cave experts on the exploration.

Once inside Son Doong, they were only allowed to walk on a small path 60m in width, and were not allowed to touch any stalagmites with their bare hands, to pick up or move anything, even a small pebble.

They also had to take out of the cave everything they had brought there, even if it was a toothpick or cigarette ash.

All of these measures help protect every centimeter of the ecosystem and the wild beauty of Son Doong.

Below are a series of photos by Luk Ban La featuring a journey to the world's biggest cave in Vietnam.

These photos were one of the entries to Tuoi Tre (Youth) newspaper's year-long competition themed “Vietnam – Country – People" concluding in October last year.

Inside Hang En

Let us spread the “Save Son Doong” message

On Doline 1 – the heart of Son Doong

On Doline 1 – the heart of Son Doong

The road to Adam’s garden

Marvelous stalagmites in Son Doong

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