When our ancestors looked up into the night sky, they too saw a great, glimmering band of light splitting the darkness. In Southeast Asia, people called it “the Silver River.” In Southern Africa, “the Backbone of the Night.” And in the West, around 2,500 years ago, it earned the name “the Milky Way.” Across the globe, civilizations had theories of what the band of light was and why it was there. But only recently have humans had the tools to get the full picture.  Today we know the Milky Way is our galaxy: two spiral arms filled with more than 100 billion stars, all rotating around a supermassive black hole. And here on our little blue planet, we’re in the middle of it all. Dr. Alok Patel speaks with two galaxy experts to find out how scientists have built the first high-resolution, three-dimensional map of the Milky Way—and what that map reveals about the formation and future of our galactic home. Learn more about NOVA and subscribe to our YouTube channel.