Fans have flocked to a church in Germany to hear a chord change in a musical composition that lasts for 639 years. It is the first change in the piece, As Slow As Possible, in seven years. The work is by the avant-garde American composer, John Cage. It began 19 years ago with a pause lasting nearly 18 months. The change of chord took place on the specially built organ on which the composition is being performed. The Saint Burchardi Church in the city of Halberstadt started playing the music in 2001 and the last note change took place in 2013....