Americanpopularmusichadagreateffectonmusicacrosstheworld.Itappearedearlyinthe19thcentury,andinthe20thcenturytheAmericanmusicindustrydevelopedaseriesofnewformsofmusic,usingbluesandotherelementsofAmericanfolkmusic.Thesepopularstylesincludedcountry,R&B,jazzandrock.The1960sand'70ssawanumberofimportantchangesinAmericanpopularmusic,includingthedevelopmentofanumberofnewstyles,suchasheavymetal,punk,soul,andhiphop.Thoughthesestyleswerenotpopularinthesenseofmainstream,theywerecommerciallyrecordedandarethusexamplesofpopularmusic.