Forgotten wall

It's an engineering feat from ancient times, but the wall constructed by the Qi State more than 2,500 years ago has been largely ignored. Zhao Ruixue chats to a man committed to exploring this slice of history.

Photographer Hu Deding, 63, never thought he would spend more than 10 years exploring an ancient engineering project seldom visited by tourists.

"I came across the ancient wall and found it so amazing. I just can't stop walking it and exploring it again and again," Hu says.