In 2001, at the former St. Burchard Church in Halberstadt, Germany, the organ version of a musical piece As Slow As Possible by John Cage started. The original version lasts for 20 minutes, but the composer’s followers decided to make it last for 639 years. Chords change every few years, and the piece is scheduled to conclude in 2640. ASLSP is considered to be the world’s longest concert in history.