A crater of Erta Ale, an active volcano in Ethiopia. [Photo by Jun Cheng/provided to China Daily]

"It's natural to search for the cradle of humanity if you're interested in anthropology," he says.

"That's East Africa, where Lucy is from."

Lucy refers to the 3.2 million-year-old skeleton of a female belonging to the early hominin species Australopithecus that was excavated in Ethiopia in 1974. She's commonly considered the oldest discovered ancestor of Homo sapiens.

Jun Cheng snapped over 100,000 photos while traveling over 20,000 km in East Africa－far beyond the Lucy site.

He pointed out a photo during a recent Beijing exhibition.