In the mountains of Nepal's Mustang region, just hours from the homeland he had never seen, Tenzin Rigzin Phurpatsang struggled to breathe the air his Tibetan ancestors had adapted to over generations. The thin air felt heavy.The 37-year-old, first-time actor was in Mustang to film “Four Rivers Six Ranges,” a historical drama about resistance fighters who helped the Dalai Lama escape Tibet in 1959. A year later, Phurpatsang's own grandfather, Yeshi Wangyal, had returned to Tibet after CIA training to lead a separate guerrilla mission. He was killed fighting Chinese forces.Born in exile in…READ FULL ARTICLE