The Wanamaker Organ

The smallest pipe is a quarter-inch in length. More than 8,000 pipes were added to the Organ between 1911 and 1917, and from 1924 to 1930 an additional 10,000 pipes were installed, bringing the total number of pipes today to 28,500.

From Friends of the Wanamaker Organ. They have an informational video that covers some of the history of this enormous musical instrument:

From the Wikipedia page:

The pipes are laid out across five floors, with the sections situated as follows:

– 2nd floor south – Main Pedal 32′, Lower Swell, Great, Percussions
– 3rd floor south – Main Pedal, Chorus, Upper Swell, Choir/Enclosed Great, Solo, Vox Humana Chorus
– 4th floor south – String
– 4th floor west – Orchestral (adjacent to String)
– 7th floor south – Major Chimes, Ethereal, Chinese Gong
– 7th floor north – Echo

The 32′ Wood Open, 32′ Diaphone, and 32′ Metal Diapason pipes run the length of a little more than 2 stories, beginning on the second floor.

Amazing.