This week, for the only the third time in its 103-year history, the “voice of Philadelphia” will fall silent. But the good news is that it’s only for a few weeks, while it gets a much needed tune-up.

The Wanamaker Grand Court Organ is the largest functioning musical instrument in the world, located within the magnificent 7-story Macy’s Center City (formerly Wanamaker’s department store) in Philadelphia, Pennsylvania.

The Wanamaker Grand Court Organ's six-manual console. (Photograph by Bob Krist)

The Wanamaker Grand Court Organ’s six-manual console. (Photograph by Bob Krist)

Originally built for the 1904 St. Louis World’s Fair, the organ came to the City of Brotherly Love when John Wanamaker purchased it for his new department store. After a freight journey across the eastern half of the U.S. (in 13 cars!), the Grand Court Organ made its debut at the retail emporium on June 22, 1911 timed to coincide with the precise moment when England’s King George V was crowned at Westminster Abbey.

Today, Grand Court Organist (just the fourth to hold the title since 1911) Peter Richard Conte performs two concerts a day, Monday through Saturday, to legions of locals and visitors who are hip to the free events. Renowned organists from all over the world have also been known to travel to Philadelphia just to work their magic on the ivory keyboards.

When the organ arrived it had more than 10,000 pipes. But even then the tone was judged inadequate to fill the lofty space, and Wanamaker’s son had the instrument outfitted with nearly triple the number of pipes. Now the 287-ton tonal wonder can put out a sound that rivals three symphony orchestras.

The smallest pipe is a quarter-inch in length and the largest is so wide around that a Shetland pony once posed inside for publicity photos.

This week, curator Curt Mangel is taking “baby” (the nickname given to the organ by those who work with her) offline for about three weeks to install a new “brain” into the organ and refurbish the console area — a move that constitutes the organ’s first official “vacation” in its long history of service. But come August, it’s back to work for this magnificent musical masterpiece.

It’s worth traveling for.

Bob Krist is a contributing photographer for National Geographic Traveler magazine and an award-winning photojournalist. See more of his work at BobKrist.com.