Following her motto "Human potential is unlimited, and I want to know where my limit is," 16-year-old Zhen Xin has already overcome numerous challenges that would astonish even adults.

This summer, Zhen accomplished the remarkable feat of climbing China's five great mountains in as many days. In a mere four days and ten hours, she successfully conquered Huashan Mountain, Songshan Mountain, Taishan Mountain, Hengshan Mountain in north China's Shanxi Province, and Hengshan Mountain in central China's Hunan Province. In doing so, she became the youngest and fastest to complete the challenge.

Zhen is no novice when it comes to such challenges - starting with her first marathon at the age of 11, she has now completed 13 marathons. When she turns 18, she wants to take on the World Marathon Challenge, which entails running seven marathons on seven continents in seven days.

While still in high school, this determined young girl, who constantly pushes her own limits, has plans to pursue a degree in psychology at university, "because I want to discover the unknown," she said.