Where can I watch Asian Corridor in Heaven in United States?

Part of the Insight Asia series, Asian Corridor In Heaven is a six-episode HD documentary series co-produced by KBS and NHK about the world's oldest trade route, the "Ancient Tea and Horse Caravan Road". Pre-dating the Silk Road by 200 years, the Ancient Tea and Horse Caravan Road crossed from the Sichuan and Yunnan provinces of Southwest China over mountainous terrain into Tibet, Nepal, and India. The Caravan Road was not only an important route for the trade of tea and horses, but also a corridor connecting Chinese and Tibetan language, people, religion, and cultures.