"20 Days in Mariupol" director and journalist Mstyslav Chernov talks with IndieWire's Brian Welk at the Sundance Film Festival about the horrors he witnessed and documented in Mariupol, Ukraine at the start of Russia's invasion in 2022. Chernov talks about his challenges as a journalist and storyteller tasked with documenting while also trying to help others and conveying that struggle on film. Chernov is joined by the film's editor Michelle Mizner and producer Vasilisa Stepanenko.