In March 2012, a 16-year-old rapper from Englewood, on the South Side of Chicago, named Chief Keef put a song called I Don't Like on YouTube. Until then he was a local artist with a YouTube following; the song spread fast.

The pivot was a remix. That May, Kanye West, who is also from Chicago, took the track into his own studio, added Pusha T, Jadakiss and Big Sean, and put it out on his G.O.O.D. Music roster. That remix is what carried drill out of the South Side and onto the national charts. A month later, Chief Keef signed to Interscope. He was still 16, a minor, and the deal needed a court's approval.

Before the genre, the context. Between 2010 and 2012, parts of the South and West Sides of Chicago were posting some of the highest murder rates in the country, and gun deaths among teenagers were a weekly fixture in the local press. The same teenagers were putting raps on YouTube about the streets they could not leave.

The sound those raps used was largely the work of one producer, Young Chop, then 18 and self-taught. His beats had three signatures: a long, cold sub-bass from the Roland 808 drum machine; fast, rattling hi-hat patterns borrowed from Atlanta's trap scene; and synth pads closer to a John Carpenter horror-film score than to anything in hip-hop's recent past. Compared to the Southern trap of the same year, drill sounded thinner, slower, emptier. The space in the beat was the point.

The track below is the one that started it. Listen once and notice how little melody there is, and how much room around each kick. That emptiness is the 2012 sound.

By 2014 the Chicago template had crossed the Atlantic. South London crews — groups like 67 and 150 out of Brixton — kept the cold pads and the rolling hi-hats. Chicago's beats feel heavy and slow because they sit in half-time, meaning the drums hit at half the speed you'd tap your foot; the London producers pushed the audible tempo up to a sprint, around 140 BPM, and bolted on a sliding, swung bassline drawn from UK garage. They called it UK drill: a Chicago dialect with a Brixton accent. Rappers from elsewhere in the city, like Headie One from Tottenham in the north, soon spread it across London.

The twist came in 2019. A 19-year-old from Canarsie, Brooklyn, named Pop Smoke linked up with a UK producer called 808Melo and released Welcome to the Party. The bassline was UK drill's; the bones of the beat were still Young Chop's 2012 sound; the voice on top was East Coast hip-hop's. Three cities sat inside a single track.

That single track proved drill had become a vessel. Pour it into any local scene and that city's own accents and slang will handle the rest.

By 2019, with Welcome to the Party, the vessel was finished; everything after that was the world filling it in. In February 2020, Pop Smoke was shot during a home invasion in the Hollywood Hills, Los Angeles. He was 20. By then the sound had outgrown any one artist. France had its own scene in the Paris suburbs, where drill fused with second-generation immigrant rap in French. Australia had OneFour out of western Sydney. Ghana had its own drill, a local strain called asakaa, out of Kumasi. Brazil and Japan both grew domestic drill micro-scenes.

From a South Side teenager's YouTube upload in 2012 to a global default language by 2019 is seven years. Hip-hop itself took most of the 1980s to make the same trip. The acceleration is the story — a teenager on YouTube can now rewire urban music faster than the industry can decide whether to take him seriously.