Watch Free Online HD Moviesjoy. Part of the Insight Asia series, 'Asian Corridor in Heaven' is a six-episode documentary series 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.