Encore: Beijing's plan to save the Great Wall

The Great Wall has survived centuries of wind and war. Now it also faces a new kind of challenge, not from nature, but from the millions who come to love it. Earlier this year, regulations to protect the Great Wall took effect in Beijing. Smarter technology. Tighter oversight. The question is whether these changes can save it from its own popularity. On the show: Steve, Fei Fei & Yushan