Some of the biggest names in hip-hop, including Eminem, Redman, Method Man, Mary J. Blige, Ghostface Killah, Public Enemy, Wale, the Roots, and Kid Rock, joined forces for a concert Wednesday night in Brooklyn to pay tribute to one of hip-hop's most influential building blocks: Def Jam Records, a label that supported formative artists like LL Cool J, the Beastie Boys, and Run-DMC.