In 1973, in the rec room of a Bronx apartment building, Clive Campbell—stage name: DJ Kool Herc—and his sister, Cindy, put on a “Back to School Jam” party. Boys paid 50 cents for entry; girls paid 25. As per his sister’s suggestion, Kool Herc used two vinyl mixers to play disco and funk tunes in a loop. His friend Coke La Rock grabbed a microphone and shouted over the track. It was a momentous occasion. Hip-hop was invented then and there, at 1520 Sedgwick Avenue.

That year, every crumbling street corner in the Bronx sprang alive with “Masters of Ceremony” (or “M.C.’s,” as they became known) and nascent D.J.’s, who remixed dated disco records. In 1979, “Rapper’s Delight,” by the Sugarhill Gang, hit the Billboard Hot 100 chart. Over the next 10 years, the obscure musical genre began to trickle into the mainstream.