It's been three years since the unchecked spread of a novel coronavirus upended our daily lives. In March 2020, offices began closing, sporting events were canceled, and frightening numbers of people started dying from Covid-19. As of today, the virus has claimed the lives of more than one million Americans and at least seven million worldwide, although experts estimate as many as 20 million may have succumbed to the virus globally. In this episode, historian John Barry, an expert on the 1918 flu pandemic and a distinguished scholar at Tulane University, delves into what the world now knows about Covid's origins, masks, vaccines, and more.