The result was the band's first single, "Türen öffnen sich zur Stadt" (Doors Open To The City), recorded in 1971. At over five minutes in length, it showed the influence of progressive rock, in particular Uriah Heep's "Gypsy," and established the Puhdys as one of East Germany's top bands. Its music was composed by Birr, who had emerged as the band's main singer, and the lyrics were written by Wolfgang Tilgner, who would remain one of the band's principal lyricists, along with Burkhard Lasch.