Pop-Rap is a marriage of hip-hop beats and raps with strong melodic hooks, which are usually featured as part of the chorus section in a standard pop-song structure. Pop-rap tends to be less aggressive and lyrically complex than most street-level hip-hop, although during the mid- to late '90s, some artists infused the style with a more hardcore attitude in an attempt to defuse backlash over their accessibility. Pop-rap got its start in the late '80s, when artists like Run-D.M.C., L.L. Cool J, and the Beastie Boys began to cross over into the mainstream.