Zhang Xinyu descends into the Marum volcano cone.

The quartet visited the capital city Mogadishu with flak vests, rifles and bodyguards, trying to find Chinese elements in the African country, which established diplomatic ties with China in 1960.

News of their arrival spread across the city, thanks to locals who once had connections with China. The visitors found a recording of Chinese revolutionary songs taped by Somalis in 1986 at the local TV station. They visited the hospital, which was built with the aid of China in the 1980s with distinct elements of Chinese architecture of that time. They met people who had worked for Chinese companies and showed employee cards they had preserved.

They also attended the opening of Somalia's first new bank since the civil war shattered much of the country's financial infrastructure, and opened an account there.

Next, the adventure seekers entered the sealed zone around the fourth reactor of the Chernobyl Nuclear Power Plant in Ukraine in August. They believe they are the first Chinese to take a video of the area after the catastrophic nuclear accident in 1986.

Then they ventured to Ambrym in Vanuatu, one of the most active volcanoes of the New Hebrides volcanic arc, at the end of November. Zhang descended 275 meters into the Marum volcano cone after donning gear to protect himself from a continuous shower of acid rain.

Only New Zealand explorer Geoff Mackley had previously lowered himself to such a depth into Marum - 400 meters in that case - after waiting for more than 30 days for more pleasant weather.

Based on the knowledge they acquired from China's national volcano research center before departure, Zhang also collected a small ball of "Pele's hair", a kind of volcano glass fiber, which is difficult to gather and transport because of its fragility, and contributed it to the center.

Living in a way so different from most Chinese, the adventure seekers are often questioned about their activities.

"Some people asked if we are crazy. We treat the expeditions as a kind of lifestyle," Liang says. "Everyone has the power to chase his dream."

Regarding safety, Liang says their expeditions focus on controlling risk. "Our team always gathers lots of scientific knowledge and makes full preparation before each journey," she says.