NPR’s Invisibilia has hit an important milestone: episodes of the podcast, which explores the invisible forces that guide human behavior, have been downloaded or streamed more than 10 million times. Invisibilia also airs on more than 300 public radio stations around the country. “This confirms that expert story-telling, approaching difficult subjects with a combination of rigorous reporting and a human perspective, works across all platforms,” said Eric Nuzum, NPR’s VP of programming.