For just the 12th time in 11 years, the note has changed in the longest concert being played in the world.

John Cage's composition "As Slow as Possible" started being performed at a German church on Sept. 5, 2001, the date of Cage's 89th birthday.

The performances started with a 17-month pause before the first note sounded in February 2003.

Thursday, the note was changed for just the 12th time.

The next note change isn't due until October 2013.

The composition isn't scheduled to end until the year 2640.

If things work out as planned, it will have been playing for 639 years when it's finished.