Hip-hop originated in the Bronx in the 1970s among African American and Latino communities. It began as a culture consisting of four main elements - rapping, DJing, breakdancing, and graffiti. Rapping involves rhythmic spoken word over beats, while DJs play music and create sounds using turntables. Breakdancing is a style of dance to hip-hop music. Graffiti involves writing and drawings on public surfaces. Hip-hop spread through block parties where DJs played and mixed genres of music for people to dance and rap over. It has since evolved into a global music genre and cultural movement centered around themes of struggle and self-expression.