When did the organ performance of John Cage’s piece begin?

The organ performance of John Cage's piece, titled "As Slow As Possible," began on September 5, 2001, in Halberstadt, Germany. This performance is noted for its exceptionally lengthy duration, spanning over several years; it is scheduled to conclude in 2640. The significance of the year 2001 marks the start of a project that tells a unique story in the context of contemporary music and performance art. This specific timeline reflects Cage's innovative approach to music, emphasizing the experience of time and sound, showcasing why this answer is appropriate.