Centering around the Shanghai International Marathon from this past Sunday, Nike and and its long-time advertising partner Wieden+Kennedy put up a total of eight street art murals showcasing the city's burgeoning running scene. The campaign, dubbed "Unstoppable," honored Shanghai's runners, who have to overcome the cramped quarters and rampant air pollution of their home city. One of the murals, by celebrated French street artist WK Interact, featured the retired pro runner Jin Yuan, who now coaches the Shanghai chapter of the Nike Run Club. The entire project was documented by Director Paul Hwang, and the resulting short film offers an exclusive behind the scenes look into the making of the mural, as well as interviews with WK Interact and Jin Yuan. Enjoy it below.