The Mexican ranchera singer Chavela Vargas was a national hero for much of her adult life; she became an international superstar at age 71. A teenage rebel, she was a sexual pioneer, a glorious musician, a friend to Frida Kahlo, Diego Rivera, Juan Rulfo, Werner Herzog and Julie Taymor, an addictive drinker and, eventually, a comeback artist, as she became a favorite of Pedro Almodovar’s, and then performing at Carnegie Hall, and receiving a Latin Grammy.  Catherine Gund and Daresha Kyi tell her remarkable story. (U.S.-Mexico, 2017, 93m)