Keith Jarrett's Köln concert

Dropped by his label, Columbia, the 29-year-old Keith Jarrett decided to play a series of totally improvised, solo piano concerts. A young German promoter set him up at the 1,400-seater Cologne Opera House for what was to be the venue's first ever jazz gig, but Jarrett was shunted into a late-night slot and given a small, out of tune baby grand piano with faulty pedals. Jarrett has since dismissed this hour-long improvisation as repetitive and simplistic juvenilia, but its soulful mix of jazz, gospel and country music proved to be extraordinarily popular, turning him into one of jazz's biggest stars and introducing him to a diverse audience. The album – on Manfred Eicher's ECM label – has since become the biggest-selling solo piano release ever.