"Jesus Walks" by Kanye West; in an era of excess, a Christian rap song challenges the church and changes its own ideals about religion and rap music.

"Alright" by Kendrick Lamar; making protest music in the era of Black Lives Matter, "Alright" becomes the unsaid anthem for hope.

"Rock Box" by Run-DMC; how one song tore down the barriers between rock and hip-hop, race and class on American radio and television.

"Elevators" by OutKast; hip-hop's Southern voice breaks through with an unsuspecting song that redefines rap's cultural and geographic boundaries.

"The Bridge" by Marley Marl and MC Shan; a song designed to foster community pride ignites hip-hop's most epic rap battle.

"Ladies First" by Queen Latifah; at the height of hip-hop's misogynistic themes, the culture bows down to their queens of rap.