Escaping 'Death Valley'

The biggest obstacle in the way was a series of staggered waterfalls reaching a total height of around 90 meters and surrounded by steep cliffs.

It's recorded that previous explorers had made it to the waterfalls but had to give up there. The only way to continue the adventure was to figure out how to get down to the bottom of the valley.

Their guides explored the arrow bamboo forests for several hours trying to find a way that would allow them to climb over the nearby mountains, but the complicated environment was unyielding.

The guides wanted to give up the journey, but Liu wanted to attempt a 120-meter descent from a nearby precipice－a bold action that he encouraged them to join.

Liu and the four other teammates taught the five guides how to use rock climbing ropes and other gear essential to make their way down－they first transported the heavy backpacks, and then the team followed.

They had to split the descent into several sections, because the total distance exceeded the length of their ropes.

It took three hours to rappel to the bottom of the valley, where they were rewarded with a splendid view.

"We sometimes used the sturdy tree roots to descend. It's a bit like the movie Tarzan of the Apes," Liu says.

"Safety is always paramount. We couldn't be any more careful. If you accidentally fall, spraining your ankle or breaking your leg, it's almost impossible to transport you beyond the rolling mountains to get treatment."

For the three nights, he barely slept.

His thoughts were consumed with how to best ensure the safety of the team. He had to make prejudgments about which direction to go and where to set up camps, based on weather and environment.

"Exploration is not risking one's life－it's about exploring one's maximum ability and the uncertainty of the destination. Exploring nature is like solving riddles, one after another," he says.

They took mechanical compasses and devices based on the satellite navigation system of Beidou and GPS, respectively. In the area with the geomagnetic anomaly, the deflection of a mechanical compass was as much as 30 degrees.

"It's an unusual phenomenon. We have given all data to geologists to unravel the riddle," Liu says.

He notes that the geomagnetic anomaly in the region causes mechanical compasses to malfunction. In the past when there were no satellite-based navigation tools, people would get lost easily in the deep mountains.