1975: Number 34 in our series of the 50 key events in the history of world and folk music

In 1975, the Swiss ethnomusicologist Marcel Cellier released recordings of an obscure Bulgarian choir. For a decade it remained an academic oddity until Bauhaus' Peter Murphy stumbled across a cassette and recommended it to Ivo Watts-Russell of the indie label 4AD. Russell tracked down and licensed the original tapes, repackaging them in 1986 as Le Mystere des Voix Bulgares. The casually forthright female vocals, haunting glissandos and dissonant harmonies struck a chord with millions: a world tour and Grammy followed.