Breaking2 was Nike's tremendously ambitious project to run a marathon in less than 2 hours. The project failed to reach its goal, but it came damn close. And in the process, the brand—and long-distance running more generally—learned new ways to shave time off future races. At the Cannes Lions, we sat down with leaders from Nike, Wieden + Kennedy and production house Dirty Robber to talk about the project's key takeaways.