In 2003, T.I. and other Atlanta rappers created new subgenre of rap: trap music. Twenty years later, its influence is everywhere. JUANA SUMMERS, HOST: About two minutes into the song, "Y'all Scared," ...

Trap is the perfect crossover between EDM and hip-hop. In fact, this genre is responsible for some of music’s hottest artists, from T.I. and Waka Flocka to, more recently, RL Grime and Flosstradamus.

From the disco samples of old school hip hop to the deadpan delivery of today's drill, American hip hop has morphed in every direction over its 50-year history, defying categorization. The Barron's ...