20th Century was a compilation album issued by Ariola in Germany during 1973. Released in a gatefold sleeve, the collection focused on Marc Bolan and T. Rex recordings from the band's most commercially successful glam rock period. The compilation assembled recent singles, B-sides and key album tracks, presenting a snapshot of T. Rex at the height of their international popularity. The album took its title from 20th Century Boy, one of Marc Bolan's best-known singles, and conc